[Crash-utility] Re: [ANNOUNCE][RFC][PATCH] Crash-utility, tracing: enable crash to analyze tracing from core-file (make tracing can act as a flight recorder)

Dave Anderson anderson at redhat.com
Tue Aug 4 16:01:03 UTC 2009


Hello Lai,

If ever there was a perfect candidate for a crash utility extension module,
this is it.  This functionality is far too subsystem-specific to included as
a generic command.  There has not been a "new" base crash command in many years.

Reviewing the patch, the "trace" command can easily be created as an extension
module.  The only things that need to be done are:

  (1) Remove the patches to the top-level "Makefile", "defs.h",
      "global_data.c", "kernel.c", "main.c" and "help.c".
 
Put your "ftrace.c" file in the "extensions" subdirectory. 
  
  (2) Put the "int nr_cpu_ids" variable into the ftrace.c extension
      module, where you still will have access to the global "kt" 
      kernel_table pointer. 
  (3) Add the relevant hooks to "ftrace.c" to make it an extension module,
      and create an accompanying "ftrace.mk" to build it.  Use "snap.c" 
      and "snap.mk" as a simple examples.  Enter "crash -h extend" for
      details on the required hooks. 
  (4) To build it, enter "make extensions" from the top-level.  If the
      "defs.h" file is available, you can just enter "make -f ftrace.mk" 
      from the build directory.     
  
Then when you need it, use the "extend" command to load the "ftrace.so" 
command extension module into any crash session, and the "ftrace" command 
will look like and behave identically to all other crash commands.

When you are satisfied with the functionality, we can put it in the "extensions"
web page at http://people.redhat.com/anderson/extensions.html (and eventually
include it in a RHEL release as a new crash extension subpackage).  You will
be designated as the upstream maintainer.

Thanks,
  Dave

PS: Note that I have sent this reply only to you and the crash-utility at redhat.com
mailing list. 

   

----- "Lai Jiangshan" <laijs at cn.fujitsu.com> wrote:

> We use tracing subsystem very well when kernel is alive.
> But we also want to get help from tracing when kernel is core-dump.
> This patch is for this purpose. It makes tracing can act as a
> flight recorder, we can find what have happen from the events.
> 
> This patch is applied for crash-4.0-8.8.
> It was tested for linux version 2.6.31-rc5-tip-00972-gd84b9d2 on
> i386.
> 
> The codes is not mature, comments are welcome.
> 
> And any request is welcome, it will be added to my plan.
> 
> Lai.
> 
> crash> help trace
> 
> NAME
>   trace - show or dump the tracing info
> 
> SYNOPSIS
>   trace [ <show [-c <cpulist>] [-f [no]<flagname>]> | <dump [-sm]
> <dest-dir>> ]
> 
> DESCRIPTION
> trace
>     shows the current tracer and other informations.
> 
> trace show [ -c <cpulist> ] [ -f [no]<flagename> ]
>     shows all events with readability text(sorted by timestamp)
>     -c: only shows specified CPUs' events.
>         ex. trace show -c 1,2    - only shows cpu#1 and cpu#2 's
> events.
>             trace show -c 0,2-7  - only shows cpu#0, cpu#2...cpu#7's
> events.
>     -f: set or clear a flag
>         available flags            default
>         context_info               true
>         sym_offset                 false
>         sym_addr                   false
>         graph_print_duration       true
>         graph_print_overhead       true
>         graph_print_abstime        false
>         graph_print_cpu            true
>         graph_print_proc           false
>         graph_print_overrun        false
> 
> trace dump [-sm] <dest-dir>
>     dump ring_buffers to dest-dir. Then you can parse it
>     by other tracing tools. The dirs and files are generated
>     the same as debugfs/tracing.
>     -m: also dump metadata of ftrace.
>     -s: also dump symbols of the kernel <not implemented>.
> 
> 
> EXAMPLE, dump ring_buffer:
> 
> crash > trace dump -m dumped_tracing
> (quit crash)
> # ls -R dumped_tracing
> dumped_tracing:
> events  per_cpu  saved_cmdlines
> 
> dumped_tracing/events:
> block  ftrace  irq  kmem  sched  skb  workqueue
> 
> dumped_tracing/events/block:
> block_bio_backmerge  block_bio_frontmerge  block_plug     
> block_rq_complete  block_rq_requeue  block_unplug_io
> block_bio_bounce     block_bio_queue       block_remap    
> block_rq_insert    block_sleeprq     block_unplug_timer
> block_bio_complete   block_getrq           block_rq_abort 
> block_rq_issue     block_split
> 
> dumped_tracing/events/block/block_bio_backmerge:
> format
> 
> dumped_tracing/events/block/block_bio_bounce:
> format
> ....
> dumped_tracing/per_cpu:
> cpu0  cpu1
> 
> dumped_tracing/per_cpu/cpu0:
> trace_pipe_raw
> 
> dumped_tracing/per_cpu/cpu1:
> trace_pipe_raw
> 
> 
> EXAMPLE, shows function tracer 
> crash > trace show
>            <...>-3677  [001]  6094.628402: pick_next_task_fair
> <-schedule
>            <...>-3677  [001]  6094.628403: pick_next_task_rt
> <-schedule
>            <...>-3677  [001]  6094.628404: pick_next_task_fair
> <-schedule
>            <...>-3677  [001]  6094.628405: pick_next_task_idle
> <-schedule
>            <...>-3677  [001]  6094.628406: calc_load_account_active
> <-pick_next_task_idle
>            <...>-3677  [001]  6094.628407: perf_counter_task_sched_out
> <-schedule
>        <swapper>-0     [001]  6094.628437: finish_task_switch
> <-schedule
>        <swapper>-0     [001]  6094.628438: perf_counter_task_sched_in
> <-finish_task_switch
>        <swapper>-0     [001]  6094.628439: _spin_unlock_irq
> <-finish_task_switch
>        <swapper>-0     [001]  6094.628440: kretprobe_table_lock_ptr
> <-kretprobe_table_lock
>        <swapper>-0     [001]  6094.628442: _spin_lock_irqsave
> <-kretprobe_table_lock
> ....
>             bash-3580  [000]  6119.756585: native_apic_mem_read
> <-default_get_apic_id
>             bash-3580  [000]  6119.756616: crash_save_cpu
> <-native_machine_crash_shutdown
>             bash-3580  [000]  6119.756687: append_elf_note
> <-crash_save_cpu
>             bash-3580  [000]  6119.756688: strlen <-append_elf_note
>             bash-3580  [000]  6119.756712: final_note
> <-crash_save_cpu
>             bash-3580  [000]  6119.756776: machine_kexec
> <-crash_kexec
>             bash-3580  [000]  6119.756824: page_address
> <-machine_kexec
> 
> EXAMPLE, shows function_graph tracer
> crash > trace show
>  1)   1.187 us    |            }
>  1)               |            hrtimer_forward() {
>  1)   1.018 us    |              ktime_add_safe();
>  1)   0.953 us    |              ktime_add_safe();
>  1)   5.419 us    |            }
>  1) + 87.322 us   |          }
>  1)   1.028 us    |          _spin_lock();
>  1)   1.779 us    |          enqueue_hrtimer();
>  1) ! 100.743 us  |        }
>  1)   1.043 us    |        _spin_unlock();
>  1)               |        tick_program_event() {
>  1)               |          tick_dev_program_event() {
>  1)   1.148 us    |            ktime_get();
> 
> EXAMPLE, shows various events
> crash > trace show
>        <swapper>-0     [001]  9349.585217: softirq_exit: vec=1
>        <swapper>-0     [001]  9349.585218: softirq_entry: vec=8
>        <swapper>-0     [001]  9349.585226: kmem_cache_free:
> call_site=c015a221 ptr=0xcfb16200
>        <swapper>-0     [001]  9349.585228: kmem_cache_free:
> call_site=c0151c32 ptr=0xcfb438c0
>        <swapper>-0     [001]  9349.585230: sched_process_free: task
> dhclient-script:3749 [120]
>        <swapper>-0     [001]  9349.585237: kfree: call_site=c017f13a
> ptr=(nil)
>        <swapper>-0     [001]  9349.585239: kmem_cache_free:
> call_site=c013b8f1 ptr=0xcf056ed0
>        <swapper>-0     [001]  9349.585241: softirq_exit: vec=8
>            <...>-3752  [000]  9349.585717: kmem_cache_alloc:
> call_site=c01b6a34 ptr=0xcf2c50b0 bytes_req=88 bytes_alloc=88
> gfp_flags=80d0
>            <...>-3752  [000]  9349.585732: kmem_cache_alloc:
> call_site=c01b95fa ptr=0xcf2c61e0 bytes_req=12 bytes_alloc=16
> gfp_flags=d0
> 
> 
> Signed-off-by: Lai Jiangshan <laijs at cn.fujitsu.com>
> ---
> diff --git a/Makefile b/Makefile
> index 4996cb2..a14ecc3 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -97,7 +97,7 @@ OBJECT_FILES=main.o tools.o global_data.o memory.o
> filesys.o help.o task.o \
>  	lkcd_x86_trace.o unwind_v1.o unwind_v2.o unwind_v3.o \
>  	unwind_x86_32_64.o \
>   	xen_hyper.o xen_hyper_command.o xen_hyper_global_data.o \
> -	xen_hyper_dump_tables.o
> +	xen_hyper_dump_tables.o ftrace.o
>  
>  # These are the current set of crash extensions sources.  They are
> not built
>  # by default unless the third command line of the "all:" stanza is
> uncommented.
> diff --git a/defs.h b/defs.h
> index 1b0950e..3bb54eb 100755
> --- a/defs.h
> +++ b/defs.h
> @@ -512,6 +512,7 @@ struct kernel_table {                   /* kernel
> data */
>  	uint kernel_version[3];
>  	uint gcc_version[3];
>  	int runq_siblings;
> +	int nr_cpu_ids;
>  	int kernel_NR_CPUS;
>  	long __per_cpu_offset[NR_CPUS];
>  	long *__rq_idx;
> @@ -3091,6 +3092,7 @@ void cmd_sys(void);          /* kernel.c */
>  void cmd_irq(void);          /* kernel.c */
>  void cmd_timer(void);        /* kernel.c */
>  void cmd_waitq(void);        /* kernel.c */
> +void cmd_ftrace(void);       /* ftrace.c */
>  void cmd_sym(void);          /* symbols.c */
>  void cmd_struct(void);       /* symbols.c */
>  void cmd_union(void);        /* symbols.c */
> @@ -3272,6 +3274,8 @@ int endian_mismatch(char *, char, ulong);
>  uint16_t swap16(uint16_t, int);
>  uint32_t swap32(uint32_t, int);
>  
> +void ftrace_init(void);
> +
>  /* 
>   *  symbols.c 
>   */
> @@ -3526,6 +3530,7 @@ extern char *help_repeat[];
>  extern char *help_runq[];
>  extern char *help_search[];
>  extern char *help_set[];
> +extern char *help_ftrace[];
>  extern char *help_sig[];
>  extern char *help_struct[];
>  extern char *help_swap[];
> diff --git a/ftrace.c b/ftrace.c
> new file mode 100644
> index 0000000..febcd05
> --- /dev/null
> +++ b/ftrace.c
> @@ -0,0 +1,2161 @@
> +#define _GNU_SOURCE
> +#include "defs.h"
> +#include <stdio.h>
> +#include <ctype.h>
> +#include <stdbool.h>
> +#include <setjmp.h>
> +
> +/* TODO: use more correct way to handle the return value of readmem()
> */
> +
> +static int verbose = 0;
> +
> +/*
> + * lockless ring_buffer and old non-lockless ring_buffer are both
> supported.
> + */
> +#define koffset(struct, member) struct##_##member##_offset
> +
> +static int ftrace_initialized;
> +static int ftrace_no_ftrace;
> +
> +static int koffset(trace_array, buffer);
> +static int koffset(tracer, name);
> +
> +static int lockless_ring_buffer;
> +
> +static int koffset(ring_buffer, pages);
> +static int koffset(ring_buffer, flags);
> +static int koffset(ring_buffer, cpus);
> +static int koffset(ring_buffer, buffers);
> +
> +static int koffset(ring_buffer_per_cpu, cpu);
> +static int koffset(ring_buffer_per_cpu, pages);
> +static int koffset(ring_buffer_per_cpu, head_page);
> +static int koffset(ring_buffer_per_cpu, tail_page);
> +static int koffset(ring_buffer_per_cpu, commit_page);
> +static int koffset(ring_buffer_per_cpu, reader_page);
> +static int koffset(ring_buffer_per_cpu, overrun);
> +static int koffset(ring_buffer_per_cpu, entries);
> +
> +static int koffset(buffer_page, read);
> +static int koffset(buffer_page, list);
> +static int koffset(buffer_page, page);
> +
> +static int koffset(list_head, next);
> +
> +static int koffset(ftrace_event_call, list);
> +static int koffset(ftrace_event_call, name);
> +static int koffset(ftrace_event_call, system);
> +static int koffset(ftrace_event_call, id);
> +static int koffset(ftrace_event_call, fields);
> +
> +static int koffset(ftrace_event_field, link);
> +static int koffset(ftrace_event_field, name);
> +static int koffset(ftrace_event_field, type);
> +static int koffset(ftrace_event_field, offset);
> +static int koffset(ftrace_event_field, size);
> +static int koffset(ftrace_event_field, is_signed);
> +
> +static int koffset(POINTER_SYM, POINTER) = 0;
> +
> +struct ring_buffer_per_cpu {
> +	ulong kaddr;
> +
> +	ulong head_page;
> +	ulong tail_page;
> +	ulong commit_page;
> +	ulong reader_page;
> +	ulong real_head_page;
> +
> +	ulong *pages;
> +	int head_page_index;
> +
> +	ulong overrun;
> +	ulong entries;
> +};
> +
> +static ulong global_trace;
> +static ulong max_tr_trace;
> +
> +static ulong global_ring_buffer;
> +static ulong max_tr_ring_buffer;
> +
> +static unsigned global_pages;
> +static unsigned max_tr_pages;
> +
> +static struct ring_buffer_per_cpu *global_buffers;
> +static struct ring_buffer_per_cpu *max_tr_buffers;
> +
> +static ulong ftrace_events;
> +static ulong current_trace;
> +static const char *current_trace_name;
> +
> +static void *page_tmp;
> +
> +/* at = ((struct *)ptr)->member */
> +#define read_value(at, ptr, struct, member)				\
> +	do {								\
> +		if (!readmem(ptr + koffset(struct, member), KVADDR,	\
> +				&at, sizeof(at), #struct " " #member,	\
> +				RETURN_ON_ERROR | QUIET))		\
> +			error(FATAL, "cannot read value, ptr%lu, %d\n", ptr, __LINE__);\
> +	} while (0)
> +
> +static void init_offsets(void)
> +{
> +#define init_offset(struct, member) koffset(struct, member)		\
> +	= MEMBER_OFFSET(#struct, #member);
> +
> +	init_offset(trace_array, buffer);
> +	init_offset(tracer, name);
> +
> +	init_offset(ring_buffer, pages);
> +	init_offset(ring_buffer, flags);
> +	init_offset(ring_buffer, cpus);
> +	init_offset(ring_buffer, buffers);
> +
> +	if (MEMBER_SIZE("ring_buffer_per_cpu", "pages") == sizeof(ulong)) {
> +		lockless_ring_buffer = 1;
> +		if (verbose)
> +			fprintf(fp, "lockless\n");
> +	}
> +
> +	init_offset(ring_buffer_per_cpu, cpu);
> +	init_offset(ring_buffer_per_cpu, pages);
> +	init_offset(ring_buffer_per_cpu, head_page);
> +	init_offset(ring_buffer_per_cpu, tail_page);
> +	init_offset(ring_buffer_per_cpu, commit_page);
> +	init_offset(ring_buffer_per_cpu, reader_page);
> +	init_offset(ring_buffer_per_cpu, overrun);
> +	init_offset(ring_buffer_per_cpu, entries);
> +
> +	init_offset(buffer_page, read);
> +	init_offset(buffer_page, list);
> +	init_offset(buffer_page, page);
> +
> +	init_offset(list_head, next);
> +
> +	init_offset(ftrace_event_call, list);
> +	init_offset(ftrace_event_call, name);
> +	init_offset(ftrace_event_call, system);
> +	init_offset(ftrace_event_call, id);
> +	init_offset(ftrace_event_call, fields);
> +
> +	init_offset(ftrace_event_field, link);
> +	init_offset(ftrace_event_field, name);
> +	init_offset(ftrace_event_field, type);
> +	init_offset(ftrace_event_field, offset);
> +	init_offset(ftrace_event_field, size);
> +	init_offset(ftrace_event_field, is_signed);
> +#undef init_offset
> +}
> +
> +static void print_offsets(void)
> +{
> +	if (!verbose)
> +		return;
> +
> +#define print_offset(struct, member) fprintf(fp,			\
> +	"koffset(" #struct ", " #member ") = %d\n", koffset(struct,
> member))
> +
> +	print_offset(trace_array, buffer);
> +	print_offset(tracer, name);
> +
> +	print_offset(ring_buffer, pages);
> +	print_offset(ring_buffer, flags);
> +	print_offset(ring_buffer, cpus);
> +	print_offset(ring_buffer, buffers);
> +
> +	print_offset(ring_buffer_per_cpu, cpu);
> +	print_offset(ring_buffer_per_cpu, pages);
> +	print_offset(ring_buffer_per_cpu, head_page);
> +	print_offset(ring_buffer_per_cpu, tail_page);
> +	print_offset(ring_buffer_per_cpu, commit_page);
> +	print_offset(ring_buffer_per_cpu, reader_page);
> +	print_offset(ring_buffer_per_cpu, overrun);
> +	print_offset(ring_buffer_per_cpu, entries);
> +
> +	print_offset(buffer_page, read);
> +	print_offset(buffer_page, list);
> +	print_offset(buffer_page, page);
> +
> +	print_offset(list_head, next);
> +
> +	print_offset(ftrace_event_call, list);
> +	print_offset(ftrace_event_call, name);
> +	print_offset(ftrace_event_call, system);
> +	print_offset(ftrace_event_call, id);
> +	print_offset(ftrace_event_call, fields);
> +
> +	print_offset(ftrace_event_field, link);
> +	print_offset(ftrace_event_field, name);
> +	print_offset(ftrace_event_field, type);
> +	print_offset(ftrace_event_field, offset);
> +	print_offset(ftrace_event_field, size);
> +	print_offset(ftrace_event_field, is_signed);
> +#undef print_offset
> +}
> +
> +static void ftrace_init_pages(struct ring_buffer_per_cpu
> *cpu_buffer,
> +		unsigned nr_pages)
> +{
> +	unsigned j;
> +	ulong head, page;
> +	ulong real_head_page = cpu_buffer->head_page;
> +
> +
> +	j = 0;
> +	cpu_buffer->pages = calloc(sizeof(ulong), nr_pages);
> +
> +	if (lockless_ring_buffer) {
> +		read_value(head, cpu_buffer->kaddr, ring_buffer_per_cpu, pages);
> +		cpu_buffer->pages[j++] = head - koffset(buffer_page, list);
> +	} else
> +		head = cpu_buffer->kaddr + koffset(ring_buffer_per_cpu, pages);
> +
> +	page = head;
> +	for (;;) {
> +		read_value(page, page, list_head, next);
> +		if (page & 3) {
> +			/* lockless_ring_buffer */
> +			page &= ~3;
> +			real_head_page = page - koffset(buffer_page, list);
> +		}
> +
> +		if (j == nr_pages)
> +			break;
> +
> +		if (page == head)
> +			error(FATAL, "pages 1\n");
> +
> +		cpu_buffer->pages[j++] = page - koffset(buffer_page, list);
> +	}
> +
> +	if (page != head)
> +		error(FATAL, "pages 2\n");
> +
> +	cpu_buffer->real_head_page = real_head_page;
> +	cpu_buffer->head_page_index = -1;
> +
> +	for (j = 0; j < nr_pages; j++) {
> +		if (cpu_buffer->pages[j] == real_head_page) {
> +			cpu_buffer->head_page_index = j;
> +			break;
> +		}
> +	}
> +
> +	if (cpu_buffer->head_page_index == -1)
> +		error(FATAL, "error for resolve head_page_index\n");
> +}
> +
> +static void ftrace_init_buffers(struct ring_buffer_per_cpu *buffers,
> +		ulong ring_buffer, unsigned pages)
> +{
> +	int i;
> +	ulong buffers_array;
> +	ulong *tmp = calloc(sizeof(ulong), kt->nr_cpu_ids);
> +
> +	read_value(buffers_array, ring_buffer, ring_buffer, buffers);
> +
> +	if (!readmem(buffers_array, KVADDR, tmp, sizeof(ulong) *
> kt->nr_cpu_ids,
> +			"ring_buffer, buffers, array", RETURN_ON_ERROR|QUIET))
> +		error(FATAL, "cannot read ring_buffer's buffers-array\n");
> +
> +	for (i = 0; i < kt->nr_cpu_ids; i++) {
> +		if (!tmp[i])
> +			continue;
> +
> +		buffers[i].kaddr = tmp[i];
> +
> +#define buffer_read_value(member) read_value(buffers[i].member,		\
> +			buffers[i].kaddr, ring_buffer_per_cpu, member)
> +
> +		buffer_read_value(head_page);
> +		buffer_read_value(tail_page);
> +		buffer_read_value(commit_page);
> +		buffer_read_value(reader_page);
> +		buffer_read_value(overrun);
> +		buffer_read_value(entries);
> +#undef buffer_read_value
> +
> +		ftrace_init_pages(buffers + i, pages);
> +
> +		if (verbose) {
> +			fprintf(fp, "overrun=%lu\n", buffers[i].overrun);
> +			fprintf(fp, "entries=%lu\n", buffers[i].entries);
> +		}
> +	}
> +
> +	free(tmp);
> +}
> +
> +static void ftrace_init_event_types(void);
> +static void ftrace_show_init(void);
> +
> +void ftrace_init(void)
> +{
> +	ulong addr;
> +	char tmp[128];
> +
> +	if (!symbol_exists("global_trace")) {
> +		ftrace_no_ftrace = 1;
> +		ftrace_initialized = 1;
> +		return;
> +	}
> +
> +	global_trace = symbol_value("global_trace");
> +	max_tr_trace = symbol_value("global_trace");
> +
> +	init_offsets();
> +	print_offsets();
> +
> +	read_value(global_ring_buffer, global_trace, trace_array, buffer);
> +	read_value(max_tr_ring_buffer, max_tr_trace, trace_array, buffer);
> +
> +	read_value(global_pages, global_ring_buffer, ring_buffer, pages);
> +	read_value(max_tr_pages, max_tr_ring_buffer, ring_buffer, pages);
> +
> +	global_buffers = calloc(sizeof(*global_buffers), kt->nr_cpu_ids);
> +	max_tr_buffers = calloc(sizeof(*max_tr_buffers), kt->nr_cpu_ids);
> +
> +	ftrace_init_buffers(global_buffers, global_ring_buffer,
> global_pages);
> +	ftrace_init_buffers(max_tr_buffers, max_tr_ring_buffer,
> max_tr_pages);
> +
> +	page_tmp = malloc(PAGESIZE());
> +
> +	ftrace_events = symbol_value("ftrace_events");
> +	ftrace_init_event_types();
> +
> +	addr = symbol_value("current_trace");
> +	read_value(current_trace, addr, POINTER_SYM, POINTER);
> +	read_value(addr, current_trace, tracer, name);
> +	read_string(addr, tmp, 128);
> +	current_trace_name = strdup(tmp);
> +
> +	ftrace_initialized = 1;
> +
> +	ftrace_show_init();
> +}
> +
> +static void ftrace_dump_page(FILE *out, ulong page)
> +{
> +	ulong raw_page;
> +
> +	read_value(raw_page, page, buffer_page, page);
> +
> +	if (!readmem(raw_page, KVADDR, page_tmp, PAGESIZE(), "get page
> context",
> +			RETURN_ON_ERROR | QUIET))
> +		error(FATAL, "cannot get page context\n");
> +
> +	fwrite(page_tmp, 1, PAGESIZE(), out);
> +}
> +
> +static void ftrace_dump_buffer(FILE *out, struct ring_buffer_per_cpu
> *cpu_buffer,
> +		unsigned pages)
> +{
> +	unsigned i;
> +
> +	ftrace_dump_page(out, cpu_buffer->reader_page);
> +
> +	if (cpu_buffer->reader_page == cpu_buffer->commit_page)
> +		return;
> +
> +	i = cpu_buffer->head_page_index;
> +	for (;;) {
> +		ftrace_dump_page(out, cpu_buffer->pages[i]);
> +
> +		if (cpu_buffer->pages[i] == cpu_buffer->commit_page)
> +			break;
> +
> +		i++;
> +		if (i == pages)
> +			i = 0;
> +
> +		if (i == cpu_buffer->head_page_index) {
> +			/* cpu_buffer->commit_page may be corrupted */
> +			break;
> +		}
> +	}
> +}
> +
> +static void ftrace_dump_buffers(const char *per_cpu_path)
> +{
> +	int i;
> +
> +	for (i = 0; i < kt->nr_cpu_ids; i++) {
> +		char *path;
> +		FILE *out;
> +
> +		if (!global_buffers[i].kaddr)
> +			continue;
> +
> +		asprintf(&path, "%s/cpu%d", per_cpu_path, i);
> +		mkdir(path, 0755);
> +		free(path);
> +
> +		asprintf(&path, "%s/cpu%d/trace_pipe_raw", per_cpu_path, i);
> +		out = fopen(path, "wb");
> +		free(path);
> +
> +		ftrace_dump_buffer(out, global_buffers + i, global_pages);
> +		fclose(out);
> +	}
> +}
> +
> +typedef uint64_t u64;
> +typedef int64_t s64;
> +typedef uint32_t u32;
> +
> +#define MAX_CACHE_ID	256
> +
> +struct ftrace_field;
> +typedef u64 (*access_op)(struct ftrace_field *aop, void *data);
> +static void ftrace_field_access_init(struct ftrace_field *f);
> +
> +struct ftrace_field {
> +	const char *name;
> +	const char *type;
> +	access_op op;
> +	int offset;
> +	int size;
> +	int is_signed;
> +};
> +
> +struct event_type;
> +struct format_context;
> +typedef void (*event_printer)(struct event_type *t, struct
> format_context *fc);
> +
> + /* SIGH, we cann't get "print fmt" from core-file */
> +
> +struct event_type {
> +	struct event_type *next;
> +	const char *system;
> +	const char *name;
> +	int plugin;
> +	event_printer printer;
> +	const char *print_fmt;
> +	int id;
> +	int nfields;
> +	struct ftrace_field *fields;
> +};
> +
> +static struct event_type *event_type_cache[MAX_CACHE_ID];
> +static struct event_type **event_types;
> +static int nr_event_types;
> +
> +/*
> + * TODO: implement event_generic_print_fmt_print() when the print
> fmt
> + * in tracing/events/$SYSTEM/$TRACE/format becomes a will-defined
> + * language.
> + */
> +static void event_generic_print_fmt_print(struct event_type *t,
> +		struct format_context *fc);
> +static void event_default_print(struct event_type *t,
> +		struct format_context *fc);
> +
> +static void ftrace_init_event_type(ulong call, struct event_type
> *aevent_type)
> +{
> +	ulong fields_addr, pos;
> +
> +	int nfields = 0, max_fields = 16;
> +	struct ftrace_field *fields;
> +
> +
> +	fields_addr = call + koffset(ftrace_event_call, fields);
> +	read_value(pos, fields_addr, list_head, next);
> +
> +	if (pos == 0) {
> +		aevent_type->nfields = 0;
> +		aevent_type->fields = NULL;
> +		if (verbose)
> +			fprintf(fp, "no field %lu\n", call);
> +		return;
> +	}
> +
> +	fields = malloc(sizeof(*fields) * max_fields);
> +
> +	while (pos != fields_addr) {
> +		ulong field = pos - koffset(ftrace_event_field, link);
> +		ulong name_addr, type_addr;
> +		char field_name[128], field_type[128];
> +		int offset, size, is_signed;
> +
> +		read_value(name_addr, field, ftrace_event_field, name);
> +		read_value(type_addr, field, ftrace_event_field, type);
> +		read_value(offset, field, ftrace_event_field, offset);
> +		read_value(size, field, ftrace_event_field, size);
> +		read_value(is_signed, field, ftrace_event_field, is_signed);
> +
> +		read_string(name_addr, field_name, 128);
> +		read_string(type_addr, field_type, 128);
> +
> +		if (nfields >= max_fields) {
> +			max_fields *= 2;
> +			fields = realloc(fields, sizeof(*fields) * max_fields);
> +		}
> +
> +		fields[nfields].name = strdup(field_name);
> +		fields[nfields].type = strdup(field_type);
> +		fields[nfields].offset = offset;
> +		fields[nfields].size = size;
> +		fields[nfields].is_signed = is_signed;
> +		ftrace_field_access_init(&fields[nfields]);
> +		nfields++;
> +
> +		read_value(pos, pos, list_head, next);
> +	}
> +
> +	aevent_type->nfields = nfields;
> +	aevent_type->fields = fields;
> +}
> +
> +static void ftrace_init_event_types(void)
> +{
> +	ulong event;
> +	int max_types = 128;
> +
> +	event_types = malloc(sizeof(*event_types) * max_types);
> +
> +	read_value(event, ftrace_events, list_head, next);
> +	while (event != ftrace_events) {
> +		ulong call = event - koffset(ftrace_event_call, list);
> +		ulong name_addr, system_addr;
> +		char name[128], system[128];
> +		int id;
> +
> +		struct event_type *aevent_type = malloc(sizeof(*aevent_type));
> +
> +		read_value(id, call, ftrace_event_call, id);
> +		read_value(name_addr, call, ftrace_event_call, name);
> +		read_value(system_addr, call, ftrace_event_call, system);
> +
> +		read_string(name_addr, name, 128);
> +		read_string(system_addr, system, 128);
> +
> +		aevent_type->system = strdup(system);
> +		aevent_type->name = strdup(name);
> +		aevent_type->id = id;
> +
> +		if (id < MAX_CACHE_ID)
> +			event_type_cache[id] = aevent_type;
> +
> +		if (nr_event_types >= max_types) {
> +			max_types *= 2;
> +			event_types = realloc(event_types,
> +					sizeof(*event_types) * max_types);
> +		}
> +		event_types[nr_event_types++] = aevent_type;
> +
> +		ftrace_init_event_type(call, aevent_type);
> +		if (!strcmp("ftrace", aevent_type->system))
> +			aevent_type->plugin = 1;
> +		else
> +			aevent_type->plugin = 0;
> +		aevent_type->printer = event_default_print;
> +
> +		read_value(event, event, list_head, next);
> +	}
> +}
> +
> +static struct ftrace_field *find_event_field(struct event_type *t,
> const char *name)
> +{
> +	int i;
> +	struct ftrace_field *f;
> +
> +	for (i = 0; i < t->nfields; i++) {
> +		f = &t->fields[i];
> +		if (!strcmp(name, f->name))
> +			return f;
> +	}
> +
> +	return NULL;
> +}
> +
> +static struct event_type *find_event_type(int id)
> +{
> +	int i;
> +
> +	if ((unsigned int)id < MAX_CACHE_ID)
> +		return event_type_cache[id];
> +
> +	for (i = 0; i < nr_event_types; i++) {
> +		if (event_types[i]->id == id)
> +			return event_types[i];
> +	}
> +
> +	return NULL;
> +}
> +
> +static
> +struct event_type *find_event_type_by_name(const char *system, const
> char *name)
> +{
> +	int i;
> +
> +	for (i = 0; i < nr_event_types; i++) {
> +		if (system && strcmp(system, event_types[i]->system))
> +			continue;
> +		if (!strcmp(name, event_types[i]->name))
> +			return event_types[i];
> +	}
> +
> +	return NULL;
> +}
> +
> +static void ftrace_dump_event_type(struct event_type *t, const char
> *path)
> +{
> +	char *format_path;
> +	FILE *out;
> +	int i;
> +
> +	asprintf(&format_path, "%s/format", path);
> +	out = fopen(format_path, "w");
> +	free(format_path);
> +
> +	fprintf(out, "name: %s\n", t->name);
> +	fprintf(out, "ID: %d\n", t->id);
> +	fprintf(out, "format:\n");
> +
> +	for (i = 0; i < t->nfields; i++) {
> +		struct ftrace_field *f = &t->fields[i];
> +
> +		fprintf(out, "\tfield:%s %s;\toffset:%d;\tsize:%d;\n",
> +				f->type, f->name, f->offset, f->size);
> +	}
> +
> +	/* TODO */
> +	fprintf(out, "\nprint fmt: \"unknow fmt from dump\"\n");
> +	fclose(out);
> +}
> +
> +static void ftrace_dump_event_types(const char *events_path)
> +{
> +	int i;
> +
> +	for (i = 0; i < nr_event_types; i++) {
> +		char *path;
> +		struct event_type *t = event_types[i];
> +
> +		asprintf(&path, "%s/%s", events_path, t->system);
> +		mkdir(path, 0755);
> +		free(path);
> +
> +		asprintf(&path, "%s/%s/%s", events_path, t->system, t->name);
> +		mkdir(path, 0755);
> +
> +		ftrace_dump_event_type(t, path);
> +		free(path);
> +	}
> +}
> +
> +struct ring_buffer_per_cpu_stream {
> +	ulong *pages;
> +	void *page_tmp;
> +	int available_pages;
> +	int curr_page_indx;
> +
> +	uint64_t ts;
> +	uint32_t *offset;
> +	uint32_t *commit;
> +};
> +
> +static
> +int ring_buffer_per_cpu_stream_init(struct ring_buffer_per_cpu
> *cpu_buffer,
> +		unsigned pages, struct ring_buffer_per_cpu_stream *s)
> +{
> +	unsigned i, count = 0;
> +
> +	s->page_tmp = malloc(PAGESIZE());
> +	if (!s->page_tmp)
> +		return -1;
> +
> +	s->pages = malloc(sizeof(ulong) * (pages + 1));
> +	if (!s->pages) {
> +		free(s->page_tmp);
> +		return -1;
> +	}
> +
> +	s->pages[count++] = cpu_buffer->reader_page;
> +
> +	if (cpu_buffer->reader_page == cpu_buffer->commit_page)
> +		goto pages_done;
> +
> +	i = cpu_buffer->head_page_index;
> +	for (;;) {
> +		s->pages[count++] = cpu_buffer->pages[i];
> +		
> +		if (cpu_buffer->pages[i] == cpu_buffer->commit_page)
> +			break;
> +
> +		i++;
> +		if (i == pages)
> +			i = 0;
> +
> +		if (i == cpu_buffer->head_page_index) {
> +			/* cpu_buffer->commit_page may be corrupted */
> +			break;
> +		}
> +	}
> +
> +pages_done:
> +	s->available_pages = count;
> +	s->curr_page_indx = -1;
> +	return 0;
> +}
> +
> +static
> +void ring_buffer_per_cpu_stream_destroy(struct
> ring_buffer_per_cpu_stream *s)
> +{
> +	free(s->page_tmp);
> +	free(s->pages);
> +}
> +
> +struct ftrace_event {
> +	uint64_t ts;
> +	int length;
> +	void *data;
> +};
> +
> +struct event {
> +	u32 type_len:5, time_delta:27;
> +};
> +
> +#define RINGBUF_TYPE_PADDING		29
> +#define RINGBUF_TYPE_TIME_EXTEND	30
> +#define RINGBUF_TYPE_TIME_STAMP		31
> +#define RINGBUF_TYPE_DATA		0 ... 28
> +
> +#define sizeof_local_t (sizeof(ulong))
> +#define PAGE_HEADER_LEN (8 + sizeof_local_t)
> +
> +static
> +void ring_buffer_per_cpu_stream_get_page(struct
> ring_buffer_per_cpu_stream *s)
> +{
> +	ulong raw_page;
> +
> +	read_value(raw_page, s->pages[s->curr_page_indx], buffer_page,
> page);
> +
> +	if (!readmem(raw_page, KVADDR, s->page_tmp, PAGESIZE(),
> +			"get page context", RETURN_ON_ERROR | QUIET))
> +		error(FATAL, "cannot get page context\n");
> +
> +	s->ts = *(u64 *)s->page_tmp;
> +	s->offset = s->page_tmp + PAGE_HEADER_LEN;
> +	s->commit = s->offset + *(ulong *)(s->page_tmp + 8) / 4;
> +}
> +
> +static
> +int ring_buffer_per_cpu_stream_pop_event(struct
> ring_buffer_per_cpu_stream *s,
> +		struct ftrace_event *res)
> +{
> +	struct event *event;
> +
> +	res->data = NULL;
> +
> +	if (s->curr_page_indx >= s->available_pages)
> +		return -1;
> +
> +again:
> +	if ((s->curr_page_indx == -1) || (s->offset >= s->commit)) {
> +		s->curr_page_indx++;
> +		if (s->curr_page_indx == s->available_pages)
> +			return -1;
> +
> +		ring_buffer_per_cpu_stream_get_page(s);
> +		if (s->offset >= s->commit)
> +			goto again;
> +	}
> +
> +	event = (void *)s->offset;
> +
> +	switch (event->type_len) {
> +	case RINGBUF_TYPE_PADDING:
> +		if (event->time_delta)
> +			s->offset += 1 + ((*(s->offset + 1) + 3) / 4);
> +		else
> +			s->offset = s->commit;
> +		goto again;
> +
> +	case RINGBUF_TYPE_TIME_EXTEND:
> +		s->ts +=event->time_delta;
> +		s->ts += ((u64)*(s->offset + 1)) << 27;
> +		s->offset += 2;
> +		goto again;
> +
> +	case RINGBUF_TYPE_TIME_STAMP:
> +		/* FIXME: not implemented */
> +		s->offset += 4;
> +		goto again;
> +
> +	case RINGBUF_TYPE_DATA:
> +		if (!event->type_len) {
> +			res->data = s->offset + 2;
> +			res->length = *(s->offset + 1) - 4;
> +
> +			s->offset += 1 + ((*(s->offset + 1) + 3) / 4);
> +		} else {
> +			res->data = s->offset + 1;
> +			res->length = event->type_len * 4;
> +
> +			s->offset += 1 + event->type_len;
> +		}
> +
> +		if (s->offset > s->commit) {
> +			fprintf(fp, "corrupt\n");
> +			res->data = NULL;
> +			goto again;
> +		}
> +
> +		s->ts += event->time_delta;
> +		res->ts = s->ts;
> +
> +		return 0;
> +
> +	default:;
> +	}
> +
> +	return -1;
> +}
> +
> +struct ring_buffer_stream {
> +	struct ring_buffer_per_cpu_stream *ss;
> +	struct ftrace_event *es;
> +	u64 ts;
> +	int popped_cpu;
> +	int pushed;
> +};
> +
> +static
> +void ring_buffer_stream_init(struct ring_buffer_stream *s, bool
> *cpulist)
> +{
> +	int cpu;
> +
> +	s->ss = malloc(sizeof(*s->ss) * kt->nr_cpu_ids);
> +	s->es = malloc(sizeof(*s->es) * kt->nr_cpu_ids);
> +
> +	for (cpu = 0; cpu < kt->nr_cpu_ids; cpu++) {
> +		s->es[cpu].data = NULL;
> +
> +		if (!global_buffers[cpu].kaddr)
> +			continue;
> +
> +		if (cpulist && !cpulist[cpu])
> +			continue;
> +
> +		ring_buffer_per_cpu_stream_init(global_buffers + cpu,
> +				global_pages, s->ss + cpu);
> +	}
> +
> +	s->ts = 0;
> +	s->popped_cpu = kt->nr_cpu_ids;
> +	s->pushed = 0;
> +}
> +
> +static
> +void ring_buffer_stream_destroy(struct ring_buffer_stream *s, bool
> *cpulist)
> +{
> +	int cpu;
> +
> +	for (cpu = 0; cpu < kt->nr_cpu_ids; cpu++) {
> +		if (!global_buffers[cpu].kaddr)
> +			continue;
> +		if (cpulist && !cpulist[cpu])
> +			continue;
> +		ring_buffer_per_cpu_stream_destroy(s->ss + cpu);
> +	}
> +
> +	free(s->ss);
> +	free(s->es);
> +}
> +
> +/* make current event be returned again at next pop */
> +static void ring_buffer_stream_push_current_event(struct
> ring_buffer_stream *s)
> +{
> +	if ((s->popped_cpu < 0) || (s->popped_cpu == kt->nr_cpu_ids))
> +		return;
> +
> +	s->pushed = 1;
> +}
> +
> +/* return the cpu# of this event */
> +static int ring_buffer_stream_pop_event(struct ring_buffer_stream
> *s,
> +		struct ftrace_event *res)
> +{
> +	int cpu, min_cpu = -1;
> +	u64 ts, min_ts;
> +
> +	res->data = NULL;
> +
> +	if (s->popped_cpu < 0)
> +		return -1;
> +
> +	if (s->popped_cpu == kt->nr_cpu_ids) {
> +		for (cpu = 0; cpu < kt->nr_cpu_ids; cpu++) {
> +			if (!global_buffers[cpu].kaddr)
> +				continue;
> +
> +			ring_buffer_per_cpu_stream_pop_event(s->ss + cpu,
> +					s->es + cpu);
> +
> +			if (!s->es[cpu].data)
> +				continue;
> +
> +			/*
> +			 * We do not have start point of time,
> +			 * determine the min_ts with heuristic way.
> +			 */
> +			ts = s->es[cpu].ts;
> +			if (min_cpu < 0 || (s64)(ts - min_ts) < 0) {
> +				min_ts = ts;
> +				min_cpu = cpu;
> +			}
> +		}
> +
> +		s->pushed = 0;
> +		goto done;
> +	}
> +
> +	if (s->pushed) {
> +		s->pushed = 0;
> +		*res = s->es[s->popped_cpu];
> +		return s->popped_cpu;
> +	}
> +
> +	ring_buffer_per_cpu_stream_pop_event(&s->ss[s->popped_cpu],
> +			&s->es[s->popped_cpu]);
> +
> +	for (cpu = 0; cpu < kt->nr_cpu_ids; cpu++) {
> +		if (!s->es[cpu].data)
> +			continue;
> +
> +		/* we have start point of time(s->ts) */
> +		ts = s->es[cpu].ts - s->ts;
> +		if (min_cpu < 0 || ts < min_ts) {
> +			min_ts = ts;
> +			min_cpu = cpu;
> +		}
> +	}
> +
> +done:
> +	s->popped_cpu = min_cpu;
> +
> +	if (min_cpu < 0)
> +		return -1;
> +
> +	s->ts = s->es[min_cpu].ts;
> +	*res = s->es[min_cpu];
> +
> +	return min_cpu;
> +}
> +
> +static u64 access_error(struct ftrace_field *f, void *data)
> +{
> +	return 0;
> +}
> +
> +static u64 access_8(struct ftrace_field *f, void *data)
> +{
> +	return *(int8_t *)(data + f->offset);
> +}
> +
> +static u64 access_16(struct ftrace_field *f, void *data)
> +{
> +	return *(int16_t *)(data + f->offset);
> +}
> +
> +static u64 access_32(struct ftrace_field *f, void *data)
> +{
> +	return *(int32_t *)(data + f->offset);
> +}
> +
> +static u64 access_64(struct ftrace_field *f, void *data)
> +{
> +	return *(int64_t *)(data + f->offset);
> +}
> +
> +static u64 access_string_local(struct ftrace_field *f, void *data)
> +{
> +	return (long)(data + *(int16_t *)(data + f->offset));
> +}
> +
> +static u64 access_string(struct ftrace_field *f, void *data)
> +{
> +	return (long)(data + f->offset);
> +}
> +
> +static u64 access_other_local(struct ftrace_field *f, void *data)
> +{
> +	return (long)(data + *(int16_t *)(data + f->offset));
> +}
> +
> +static u64 access_other(struct ftrace_field *f, void *data)
> +{
> +	return (long)(data + f->offset);
> +}
> +
> +static void ftrace_field_access_init(struct ftrace_field *f)
> +{
> +	/* guess whether it is string array */
> +	if (!strncmp(f->type, "__data_loc", sizeof("__data_loc") - 1)) {
> +		if (f->size != 2) {
> +			/* TODO: kernel side may be changed, need fix */
> +			f->op = access_error;
> +		} else if (strstr(f->type, "char")) {
> +			/* TODO: finish kernel side. */
> +			f->op = access_string_local;
> +		} else {
> +			/* TODO: finish kernel side. */
> +			f->op = access_other;
> +		}
> +	} else if (strchr(f->type, '[')) {
> +		if (strstr(f->type, "char"))
> +			f->op = access_string;
> +		else
> +			f->op = access_other;
> +	} else {
> +		switch (f->size) {
> +		case 1: f->op = access_8; break;
> +		case 2: f->op = access_16; break;
> +		case 4: f->op = access_32; break;
> +		case 8: f->op = access_64; break;
> +		default: f->op = access_other; break;
> +		}
> +	}
> +}
> +
> +static void show_basic_info(void)
> +{
> +	fprintf(fp, "current tracer is %s\n", current_trace_name);
> +}
> +
> +static void dump_saved_cmdlines(const char *dump_tracing_dir)
> +{
> +	char *path;
> +	FILE *out;
> +	int i;
> +	struct task_context *tc;
> +
> +	asprintf(&path, "%s/saved_cmdlines", dump_tracing_dir);
> +	out = fopen(path, "w");
> +	free(path);
> +
> +	tc = FIRST_CONTEXT();
> +        for (i = 0; i < RUNNING_TASKS(); i++)
> +		fprintf(out, "%d %s\n", (int)tc[i].pid, tc[i].comm);
> +
> +	fclose(out);
> +}
> +
> +static void ftrace_dump(int argc, char *argv[])
> +{
> +	int c;
> +	int dump_meta_data = 0;
> +	int dump_symbols = 0;
> +	char *dump_tracing_dir;
> +	char *path;
> +	int ret;
> +
> +        while ((c = getopt(argc, argv, "sm")) != EOF) {
> +                switch(c)
> +		{
> +		case 's':
> +			dump_symbols = 1;
> +			break;
> +		case 'm':
> +			dump_meta_data = 1;
> +			break;
> +		default:
> +			cmd_usage(pc->curcmd, SYNOPSIS);
> +			return;
> +		}
> +	}
> +
> +	if (argc - optind == 0) {
> +		dump_tracing_dir = "dump_tracing_dir";
> +	} else if (argc - optind == 1) {
> +		dump_tracing_dir = argv[optind];
> +	} else {
> +		cmd_usage(pc->curcmd, SYNOPSIS);
> +		return;
> +	}
> +
> +	ret = mkdir(dump_tracing_dir, 0755);
> +	if (ret < 0)
> +		return;
> +
> +	asprintf(&path, "%s/per_cpu", dump_tracing_dir);
> +	mkdir(path, 0755);
> +	ftrace_dump_buffers(path);
> +	free(path);
> +
> +	if (dump_meta_data) {
> +		asprintf(&path, "%s/events", dump_tracing_dir);
> +		mkdir(path, 0755);
> +		ftrace_dump_event_types(path);
> +		free(path);
> +
> +		dump_saved_cmdlines(dump_tracing_dir);
> +	}
> +
> +	if (dump_symbols) {
> +		fprintf(fp, "\n-s option hasn't been implemented.\n");
> +		fprintf(fp, "symbols is not dumpped.\n");
> +		fprintf(fp, "You can use `sym -l > %s/kallsyms`\n\n",
> +				dump_tracing_dir);
> +	}
> +}
> +
> +static char show_event_buf[4096];
> +static int show_event_pos;
> +
> +#define INVALID_ACCESS_FIELD 1
> +static jmp_buf show_event_env;
> +
> +struct format_context {
> +	struct ring_buffer_stream stream;
> +	struct ftrace_event event;
> +	int cpu;
> +};
> +
> +static struct format_context format_context;
> +
> +/* !!!! @event_type and @field_name should be const for every call
> */
> +#define access_field(event_type, data, field_name)			\
> +({									\
> +	static struct ftrace_field *__access_field##_field;		\
> +									\
> +	if (!__access_field##_field) {					\
> +		__access_field##_field = find_event_field(event_type,	\
> +				field_name);				\
> +	}								\
> +									\
> +	if (!__access_field##_field) {					\
> +		event_type->printer = event_default_print;		\
> +		ring_buffer_stream_push_current_event(&format_context.stream);\
> +		longjmp(show_event_env, INVALID_ACCESS_FIELD);		\
> +	}								\
> +									\
> +	__access_field##_field->op(__access_field##_field, data);	\
> +})
> +
> +static int ftrace_event_get_id(void *data)
> +{
> +	return access_field(event_types[0], data, "common_type");
> +}
> +
> +static int ftrace_event_get_pid(void *data)
> +{
> +	return access_field(event_types[0], data, "common_pid");
> +}
> +
> +#define event_printf(fmt, args...)					\
> +do {									\
> +	show_event_pos += snprintf(show_event_buf + show_event_pos,	\
> +			sizeof(show_event_buf) - show_event_pos,	\
> +			fmt, ##args);					\
> +} while (0)
> +
> +
> +static void event_field_print(struct ftrace_field *f, u64 value)
> +{
> +	if (f->op == access_error) {
> +		event_printf("<Error>");
> +	} else if (f->op == access_8) {
> +		if (f->is_signed)
> +			event_printf("%d", (int8_t)value);
> +		else
> +			event_printf("%u", (uint8_t)value);
> +	} else if (f->op == access_16) {
> +		if (f->is_signed)
> +			event_printf("%d", (int16_t)value);
> +		else
> +			event_printf("%u", (uint16_t)value);
> +	} else if (f->op == access_32) {
> +		if (f->is_signed)
> +			event_printf("%d", (int32_t)value);
> +		else
> +			event_printf("%u", (uint32_t)value);
> +	} else if (f->op == access_64) {
> +		if (f->is_signed)
> +			event_printf("%lld", (long long)value);
> +		else
> +			event_printf("%llu", (unsigned long long)value);
> +	} else if (f->op == access_string_local) {
> +		event_printf("%s", (char *)(long)value);
> +	} else if (f->op == access_string) {
> +		event_printf("%.*s", f->size, (char *)(long)value);
> +	} else if (f->op == access_other) {
> +		/* TODO */
> +	} else if (f->op == access_other_local) {
> +		/* TODO */
> +	} else {
> +		/* TODO */
> +	}
> +}
> +
> +static void get_comm_from_pid(int pid, char *comm)
> +{
> +	int li, hi;
> +	struct task_context *tc;
> +
> +	if (pid == 0) {
> +		strcpy(comm, "<swapper>");
> +		return;
> +	}
> +
> +	tc = FIRST_CONTEXT();
> +
> +	li = 0;
> +	hi = RUNNING_TASKS();
> +	while (li < hi) {
> +		int mid = (li + hi) / 2;
> +
> +		if (tc[mid].pid > pid)
> +			hi = mid;
> +		else if (tc[mid].pid < pid)
> +			li = mid + 1;
> +		else {
> +			strcpy(comm, tc[mid].comm);
> +			return;
> +		}
> +	}
> +
> +	strcpy(comm, "<...>");
> +}
> +
> +static void event_context_print(struct event_type *t, struct
> format_context *fc)
> +{
> +	u64 time = fc->event.ts / 1000;
> +	ulong sec = time / 1000000;
> +	ulong usec = time % 1000000;
> +	int pid = ftrace_event_get_pid(fc->event.data);
> +	char comm[20];
> +
> +	get_comm_from_pid(pid, comm);
> +	event_printf("%16s-%-5d [%03d] %5lu.%06lu: ",
> +			comm, pid, fc->cpu, sec, usec);
> +}
> +
> +static int gopt_context_info;
> +static int gopt_sym_offset;
> +static int gopt_sym_addr;
> +
> +static int gopt_graph_print_duration;
> +static int gopt_graph_print_overhead;
> +static int gopt_graph_print_abstime;
> +static int gopt_graph_print_cpu;
> +static int gopt_graph_print_proc;
> +static int gopt_graph_print_overrun;
> +
> +static void set_all_flags_default(void)
> +{
> +	gopt_context_info = 1;
> +	gopt_sym_offset = 0;
> +	gopt_sym_addr = 0;
> +
> +	gopt_graph_print_duration = 1;
> +	gopt_graph_print_overhead = 1;
> +	gopt_graph_print_abstime = 0;
> +	gopt_graph_print_cpu = 1;
> +	gopt_graph_print_proc = 0;
> +	gopt_graph_print_overrun = 0;
> +}
> +
> +static void set_clear_flag(const char *flag_name, int set)
> +{
> +	if (!strcmp(flag_name, "context_info"))
> +		gopt_context_info = set;
> +	else if (!strcmp(flag_name, "sym_offset"))
> +		gopt_sym_offset = set;
> +	else if (!strcmp(flag_name, "sym_addr"))
> +		gopt_sym_addr = set;
> +	else if (!strcmp(flag_name, "graph_print_duration"))
> +		gopt_graph_print_duration = set;
> +	else if (!strcmp(flag_name, "graph_print_overhead"))
> +		gopt_graph_print_overhead = set;
> +	else if (!strcmp(flag_name, "graph_print_abstime"))
> +		gopt_graph_print_abstime = set;
> +	else if (!strcmp(flag_name, "graph_print_cpu"))
> +		gopt_graph_print_cpu = set;
> +	else if (!strcmp(flag_name, "graph_print_proc"))
> +		gopt_graph_print_proc = set;
> +	else if (!strcmp(flag_name, "graph_print_overrun"))
> +		gopt_graph_print_overrun = set;
> +	/* invalid flage_name is omitted. */
> +}
> +
> +static int tracer_no_event_context;
> +static int ftrace_show_disabled;
> +
> +static void ftrace_show_function_graph_init(void);
> +static void ftrace_show_function_init(void);
> +static void ftrace_show_trace_event_init(void);
> +
> +static void ftrace_show_init(void)
> +{
> +	/* ftrace_event_get_id(), ftrace_event_get_pid() should not failed.
> */
> +	if (!find_event_field(event_types[0], "common_type")) {
> +		ftrace_show_disabled = 1;
> +		return;
> +	}
> +
> +	if (!find_event_field(event_types[0], "common_pid")) {
> +		ftrace_show_disabled = 1;
> +		return;
> +	}
> +
> +	ftrace_show_function_init();
> +	ftrace_show_function_graph_init();
> +	ftrace_show_trace_event_init();
> +}
> +
> +void show_event(struct format_context *fc)
> +{
> +	struct event_type *etype;
> +	int id;
> +
> +	id = ftrace_event_get_id(fc->event.data);
> +	etype = find_event_type(id);
> +
> +	if (!etype) {
> +		event_printf("<Unknown event type>\n");
> +		return;
> +	}
> +
> +	if (!tracer_no_event_context && gopt_context_info)
> +		event_context_print(etype, fc);
> +	if (!etype->plugin)
> +		event_printf("%s: ", etype->name);
> +	etype->printer(etype, fc);
> +}
> +
> +static int parse_cpulist(bool *cpulist, const char *cpulist_str, int
> len)
> +{
> +	unsigned a, b;
> +	const char *s = cpulist_str;
> +
> +	memset(cpulist, 0, sizeof(bool) * len);
> +
> +	do {
> +		if (!isdigit(*s))
> +			return -1;
> +		b = a = strtoul(s, (char **)&s, 10);
> +		if (*s == '-') {
> +			s++;
> +			if (!isdigit(*s))
> +				return -1;
> +			b = strtoul(s, (char **)&s, 10);
> +		}
> +		if (!(a <= b))
> +			return -1;
> +		if (b >= len)
> +			return -1;
> +		while (a <= b) {
> +			cpulist[a] = true;
> +			a++;
> +		}
> +		if (*s == ',')
> +			s++;
> +	} while (*s != '\0' && *s != '\n');
> +
> +	return 0;
> +}
> +
> +static void ftrace_show_function_graph_start(void);
> +
> +static void ftrace_show(int argc, char *argv[])
> +{
> +	int c;
> +	bool *cpulist = NULL;
> +
> +	if (ftrace_show_disabled) {
> +		fprintf(fp, "trace show is disabled.");
> +		return;
> +	}
> +
> +	set_all_flags_default();
> +	ftrace_show_function_graph_start();
> +
> +        while ((c = getopt(argc, argv, "f:c:")) != EOF) {
> +                switch(c)
> +		{
> +		case 'f':
> +			if (optarg[0] == 'n' && optarg[1] == 'o')
> +				set_clear_flag(optarg + 2, 0);
> +			else
> +				set_clear_flag(optarg, 1);
> +			break;
> +		case 'c':
> +			if (cpulist)
> +				goto err_arg;
> +			cpulist = alloca(sizeof(bool) * kt->nr_cpu_ids);
> +			if (parse_cpulist(cpulist, optarg, kt->nr_cpu_ids) < 0)
> +				goto err_arg;
> +			break;
> +		default:
> +			goto err_arg;
> +		}
> +	}
> +
> +	if (argc - optind != 0) {
> +err_arg:
> +		cmd_usage(pc->curcmd, SYNOPSIS);
> +		return;
> +	}
> +
> +	ring_buffer_stream_init(&format_context.stream, cpulist);
> +
> +	/* Ignore setjmp()'s return value, no special things to do. */
> +	setjmp(show_event_env);
> +
> +	for (;;) {
> +		show_event_pos = 0;
> +		format_context.cpu = ring_buffer_stream_pop_event(
> +				&format_context.stream, &format_context.event);
> +		if (format_context.cpu < 0)
> +			break;
> +
> +		show_event(&format_context);
> +		fprintf(fp, "%s", show_event_buf);
> +	}
> +
> +	ring_buffer_stream_destroy(&format_context.stream, cpulist);
> +
> +}
> +
> +void cmd_ftrace(void)
> +{
> +	if (ftrace_no_ftrace) {
> +		fprintf(fp, "No tracing in this kernel\n");
> +		return;
> +	}
> +
> +	if (!ftrace_initialized) {
> +		fprintf(fp, "failed to init tracing\n");
> +		return;
> +	}
> +
> +	if (argcnt == 1)
> +		show_basic_info();
> +	else if (!strcmp(args[1], "dump"))
> +		ftrace_dump(argcnt - 1, args + 1);
> +	else if (!strcmp(args[1], "show"))
> +		ftrace_show(argcnt - 1, args + 1);
> +	else
> +		cmd_usage(pc->curcmd, SYNOPSIS);
> +}
> +
> +static void event_default_print(struct event_type *t, struct
> format_context *fc)
> +{
> +	int i;
> +
> +	/* Skip the common types */
> +	for (i = t->nfields - 6; i >= 0; i--) {
> +		struct ftrace_field *f;
> +		u64 value;
> +
> +		f = &t->fields[i];
> +		value = f->op(f, fc->event.data);
> +		event_printf("%s=", f->name);
> +		event_field_print(f, value);
> +		if (i)
> +			event_printf(", ");
> +	}
> +
> +	event_printf("\n");
> +}
> +
> +static void sym_print(ulong sym, int opt_offset)
> +{
> +	if (!sym) {
> +		event_printf("0");
> +	} else {
> +		ulong offset;
> +		struct syment *se;
> +
> +		se = value_search(sym, &offset);
> +		if (se) {
> +			event_printf("%s", se->name);
> +			if (opt_offset)
> +				event_printf("+%lu", offset);
> +		}
> +	}
> +}
> +
> +static void event_fn_print(struct event_type *t, struct
> format_context *fc)
> +{
> +	unsigned long ip = access_field(t, fc->event.data, "ip");
> +	unsigned long parent_ip = access_field(t, fc->event.data,
> "parent_ip");
> +
> +	sym_print(ip, gopt_sym_offset);
> +	if (gopt_sym_addr)
> +		event_printf("<%lx>", ip);
> +
> +	event_printf(" <-");
> +
> +	sym_print(parent_ip, gopt_sym_offset);
> +	if (gopt_sym_addr)
> +		event_printf("<%lx>", parent_ip);
> +
> +	event_printf("\n");
> +}
> +
> +static void ftrace_show_function_init(void)
> +{
> +	struct event_type *t = find_event_type_by_name("ftrace",
> "function");
> +
> +	if (t)
> +		t->printer = event_fn_print;
> +}
> +
> +#if 0
> +/* simple */
> +static void event_fn_entry_print(struct event_type *t, struct
> format_context *fc)
> +{
> +	ulong func = access_field(t, fc->event.data, "graph_ent.func");
> +	int depth = access_field(t, fc->event.data, "graph_ent.depth");
> +
> +	event_printf("%*s", depth, " ");
> +	sym_print(func, gopt_sym_offset);
> +	if (gopt_sym_addr)
> +		event_printf("<%lx>", func);
> +	event_printf("() {");
> +}
> +
> +static void event_fn_return_print(struct event_type *t, struct
> format_context *fc)
> +{
> +	ulong func = access_field(t, fc->event.data, "ret.func");
> +	u64 calltime = access_field(t, fc->event.data, "ret.calltime");
> +	u64 rettime = access_field(t, fc->event.data, "ret.rettime");
> +	int depth = access_field(t, fc->event.data, "ret.depth");
> +
> +	event_printf("%*s} %lluns", depth, " ",
> +			(unsigned long long)(rettime - calltime));
> +}
> +
> +static void ftrace_show_function_graph_init(void)
> +{
> +	struct event_type *t1 = find_event_type_by_name(
> +			"ftrace", "funcgraph_entry");
> +	struct event_type *t2 = find_event_type_by_name(
> +			"ftrace", "funcgraph_exit");
> +
> +	if (!t1 || !t2)
> +		return;
> +
> +	t1->printer = event_fn_entry_print;
> +	t2->printer = event_fn_return_print;
> +}
> +#endif
> +
> +
> +#define TRACE_GRAPH_PROCINFO_LENGTH	14
> +#define TRACE_GRAPH_INDENT		2
> +
> +static int max_bytes_for_cpu;
> +static int *cpus_prev_pid;
> +
> +static int function_graph_entry_id;
> +static int function_graph_return_id;
> +static struct event_type *function_graph_entry_type;
> +static struct event_type *function_graph_return_type;
> +
> +static void ftrace_show_function_graph_start(void)
> +{
> +	int i;
> +
> +	if (!cpus_prev_pid)
> +		return;
> +
> +	for (i = 0; i < kt->nr_cpu_ids; i++)
> +		cpus_prev_pid[i] = -1;
> +}
> +
> +static void fn_graph_proc_print(int pid)
> +{
> +	int pid_strlen, comm_strlen;
> +	char pid_str[20];
> +	char comm[20] = "<...>";
> +
> +	pid_strlen = sprintf(pid_str, "%d", pid);
> +	comm_strlen = TRACE_GRAPH_PROCINFO_LENGTH - 1 - pid_strlen;
> +
> +	get_comm_from_pid(pid, comm);
> +	event_printf("%*.*s-%s", comm_strlen, comm_strlen, comm, pid_str);
> +}
> +
> +/* If the pid changed since the last trace, output this event */
> +static void fn_graph_proc_switch_print(int pid, int cpu)
> +{
> +	int prev_pid = cpus_prev_pid[cpu];
> +
> +	cpus_prev_pid[cpu] = pid;
> +	if ((prev_pid == pid) || (prev_pid == -1))
> +		return;
> +
> +/*
> + * Context-switch trace line:
> +
> + ------------------------------------------
> + | 1)  migration/0--1  =>  sshd-1755
> + ------------------------------------------
> +
> + */
> +
> +	event_printf(" ------------------------------------------\n");
> +	event_printf(" %*d) ", max_bytes_for_cpu, cpu);
> +	fn_graph_proc_print(prev_pid);
> +	event_printf(" => ");
> +	fn_graph_proc_print(pid);
> +	event_printf("\n ------------------------------------------\n\n");
> +}
> +
> +/* Signal a overhead of time execution to the output */
> +static void fn_graph_overhead_print(unsigned long long duration)
> +{
> +	const char *s = "  ";
> +
> +	/* If duration disappear, we don't need anything */
> +	if (!gopt_graph_print_duration)
> +		return;
> +
> +	/* duration == -1 is for non nested entry or return */
> +	if ((duration != -1) && gopt_graph_print_overhead) {
> +		/* Duration exceeded 100 msecs */
> +		if (duration > 100000ULL)
> +			s = "! ";
> +		/* Duration exceeded 10 msecs */
> +		else if (duration > 10000ULL)
> +			s = "+ ";
> +	}
> +
> +	event_printf(s);
> +}
> +
> +static void fn_graph_abstime_print(u64 ts)
> +{
> +	u64 time = ts / 1000;
> +	unsigned long sec = time / 1000000;
> +	unsigned long usec = time % 1000000;
> +
> +	event_printf("%5lu.%06lu |  ", sec, usec);
> +}
> +
> +static void fn_graph_irq_print(int type)
> +{
> +	/* TODO: implement it. */
> +}
> +
> +static void fn_graph_duration_print(unsigned long long duration)
> +{
> +	/* log10(ULONG_MAX) + '\0' */
> +	char msecs_str[21];
> +	char nsecs_str[5];
> +	int len;
> +	unsigned long nsecs_rem = duration % 1000;
> +
> +	duration = duration / 1000;
> +	len = sprintf(msecs_str, "%lu", (unsigned long) duration);
> +
> +	/* Print msecs */
> +	event_printf("%s", msecs_str);
> +
> +	/* Print nsecs (we don't want to exceed 7 numbers) */
> +	if (len < 7) {
> +		snprintf(nsecs_str, 8 - len, "%03lu", nsecs_rem);
> +		event_printf(".%s", nsecs_str);
> +
> +		len += strlen(nsecs_str);
> +	}
> +
> +	if (len > 7)
> +		len = 7;
> +
> +	event_printf(" us %*s|  ", 7 - len, "");
> +}
> +
> +/* Case of a leaf function on its call entry */
> +static void fn_graph_entry_leaf_print(void *entry_data, void
> *exit_data)
> +{
> +	struct event_type *t = function_graph_return_type;
> +
> +	u64 calltime = access_field(t, exit_data, "ret.calltime");
> +	u64 rettime = access_field(t, exit_data, "ret.rettime");
> +	u64 duration = rettime - calltime;
> +	int depth = access_field(t, exit_data, "ret.depth");
> +	ulong func = access_field(t, exit_data, "ret.func");
> +
> +	fn_graph_overhead_print(duration);
> +	if (gopt_graph_print_duration)
> +		fn_graph_duration_print(duration);
> +
> +	event_printf("%*s", depth * TRACE_GRAPH_INDENT, "");
> +	sym_print(func, 0);
> +	event_printf("();\n");
> +}
> +
> +static void fn_graph_entry_nested_print(struct event_type *t, void
> *data)
> +{
> +	int depth = access_field(t, data, "graph_ent.depth");
> +	ulong func = access_field(t, data, "graph_ent.func");
> +
> +	fn_graph_overhead_print(-1);
> +
> +	/* No time */
> +	if (gopt_graph_print_duration)
> +		event_printf("            |  ");
> +
> +	event_printf("%*s", depth * TRACE_GRAPH_INDENT, "");
> +	sym_print(func, 0);
> +	event_printf("() {\n");
> +}
> +
> +static void fn_graph_prologue_print(int cpu, u64 ts, int pid, int
> type)
> +{
> +	fn_graph_proc_switch_print(pid, cpu);
> +
> +	if (type)
> +		fn_graph_irq_print(type);
> +
> +	if (gopt_graph_print_abstime)
> +		fn_graph_abstime_print(ts);
> +
> +	if (gopt_graph_print_cpu)
> +		 event_printf(" %*d) ", max_bytes_for_cpu, cpu);
> +
> +	if (gopt_graph_print_proc) {
> +		fn_graph_proc_print(pid);
> +		event_printf(" | ");
> +	}
> +}
> +
> +static void *get_return_for_leaf(struct event_type *t,
> +		struct format_context *fc, void *curr_data)
> +{
> +	int cpu;
> +	struct ftrace_event next;
> +	ulong entry_func, exit_func;
> +
> +	cpu = ring_buffer_stream_pop_event(&fc->stream, &next);
> +
> +	if (cpu < 0)
> +		goto not_leaf;
> +
> +	if (ftrace_event_get_id(next.data) != function_graph_return_id)
> +		goto not_leaf;
> +
> +	if (ftrace_event_get_pid(curr_data) !=
> ftrace_event_get_pid(next.data))
> +		goto not_leaf;
> +
> +	entry_func = access_field(t, curr_data, "graph_ent.func");
> +	exit_func = access_field(function_graph_return_type, next.data,
> +			"ret.func");
> +
> +	if (entry_func != exit_func)
> +		goto not_leaf;
> +
> +	return next.data;
> +
> +not_leaf:
> +	ring_buffer_stream_push_current_event(&fc->stream);
> +	return NULL;
> +}
> +
> +static
> +void event_fn_entry_print(struct event_type *t, struct format_context
> *fc)
> +{
> +	void *leaf_ret_data = NULL, *curr_data = fc->event.data, *data;
> +	int pid = ftrace_event_get_pid(curr_data);
> +
> +	fn_graph_prologue_print(fc->cpu, fc->event.ts, pid, 1);
> +
> +	data = alloca(fc->event.length);
> +	if (data) {
> +		memcpy(data, fc->event.data, fc->event.length);
> +		curr_data = data;
> +		leaf_ret_data = get_return_for_leaf(t, fc, curr_data);
> +	}
> +
> +	if (leaf_ret_data)
> +		return fn_graph_entry_leaf_print(curr_data, leaf_ret_data);
> +	else
> +		return fn_graph_entry_nested_print(t, curr_data);
> +}
> +
> +static
> +void event_fn_return_print(struct event_type *t, struct
> format_context *fc)
> +{
> +	void *data = fc->event.data;
> +	int pid = ftrace_event_get_pid(data);
> +
> +	u64 calltime = access_field(t, data, "ret.calltime");
> +	u64 rettime = access_field(t, data, "ret.rettime");
> +	u64 duration = rettime - calltime;
> +	int depth = access_field(t, data, "ret.depth");
> +
> +	fn_graph_prologue_print(fc->cpu, fc->event.ts, pid, 0);
> +	fn_graph_overhead_print(duration);
> +
> +	if (gopt_graph_print_duration)
> +		fn_graph_duration_print(duration);
> +
> +	event_printf("%*s}\n", depth * TRACE_GRAPH_INDENT, "");
> +
> +	if (gopt_graph_print_overrun) {
> +		unsigned long overrun = access_field(t, data, "ret.overrun");
> +		event_printf(" (Overruns: %lu)\n", overrun);
> +	}
> +
> +	fn_graph_irq_print(0);
> +}
> +
> +static void ftrace_show_function_graph_init(void)
> +{
> +	if (strcmp(current_trace_name, "function_graph"))
> +		return;
> +
> +	function_graph_entry_type = find_event_type_by_name(
> +			"ftrace", "funcgraph_entry");
> +	function_graph_return_type = find_event_type_by_name(
> +			"ftrace", "funcgraph_exit");
> +
> +	if (!function_graph_entry_type || !function_graph_return_type)
> +		return;
> +
> +	/*
> +	 * Because of get_return_for_leaf(), the exception handling
> +	 * of access_field() is not work for function_graph. So we need
> +	 * to ensure access_field() will not failed for these fields.
> +	 *
> +	 * I know these will not failed. I just ensure it.
> +	 */
> +
> +	if (!find_event_field(function_graph_entry_type, "graph_ent.func"))
> +		return;
> +
> +	if (!find_event_field(function_graph_entry_type,
> "graph_ent.depth"))
> +		return;
> +
> +	if (!find_event_field(function_graph_return_type, "ret.func"))
> +		return;
> +
> +	if (!find_event_field(function_graph_return_type, "ret.calltime"))
> +		return;
> +
> +	if (!find_event_field(function_graph_return_type, "ret.rettime"))
> +		return;
> +
> +	if (!find_event_field(function_graph_return_type, "ret.overrun"))
> +		return;
> +
> +	if (!find_event_field(function_graph_return_type, "ret.depth"))
> +		return;
> +
> +	cpus_prev_pid = malloc(sizeof(int) * kt->nr_cpu_ids);
> +	if (!cpus_prev_pid)
> +		return;
> +
> +	max_bytes_for_cpu = snprintf(NULL, 0, "%d", kt->nr_cpu_ids - 1);
> +
> +	function_graph_entry_id = function_graph_entry_type->id;
> +	function_graph_return_id = function_graph_return_type->id;
> +
> +	/* OK, set the printer for function_graph. */
> +	tracer_no_event_context = 1;
> +	function_graph_entry_type->printer = event_fn_entry_print;
> +	function_graph_return_type->printer = event_fn_return_print;
> +}
> +
> +static void event_sched_kthread_stop_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("task %s:%d\n",
> +			(char *)(long)access_field(t, fc->event.data, "comm"),
> +			(int)access_field(t, fc->event.data, "pid"));
> +}
> +
> +static void event_sched_kthread_stop_ret_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("ret %d\n", (int)access_field(t, fc->event.data,
> "ret"));
> +}
> +
> +static void event_sched_wait_task_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("task %s:%d [%d]\n",
> +			(char *)(long)access_field(t, fc->event.data, "comm"),
> +			(int)access_field(t, fc->event.data, "pid"),
> +			(int)access_field(t, fc->event.data, "prio"));
> +}
> +
> +static void event_sched_wakeup_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("task %s:%d [%d] success=%d\n",
> +			(char *)(long)access_field(t, fc->event.data, "comm"),
> +			(int)access_field(t, fc->event.data, "pid"),
> +			(int)access_field(t, fc->event.data, "prio"),
> +			(int)access_field(t, fc->event.data, "success"));
> +}
> +
> +static void event_sched_wakeup_new_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("task %s:%d [%d] success=%d\n",
> +			(char *)(long)access_field(t, fc->event.data, "comm"),
> +			(int)access_field(t, fc->event.data, "pid"),
> +			(int)access_field(t, fc->event.data, "prio"),
> +			(int)access_field(t, fc->event.data, "success"));
> +}
> +
> +static void event_sched_switch_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	char *prev_comm = (char *)(long)access_field(t, fc->event.data,
> +			"prev_comm");
> +	int prev_pid = access_field(t, fc->event.data, "prev_pid");
> +	int prev_prio = access_field(t, fc->event.data, "prev_prio");
> +
> +	int prev_state = access_field(t, fc->event.data, "prev_state");
> +
> +	char *next_comm = (char *)(long)access_field(t, fc->event.data,
> +			"next_comm");
> +	int next_pid = access_field(t, fc->event.data, "next_pid");
> +	int next_prio = access_field(t, fc->event.data, "next_prio");
> +
> +	event_printf("task %s:%d [%d] (", prev_comm, prev_pid, prev_prio);
> +
> +	if (prev_state == 0) {
> +		event_printf("R");
> +	} else {
> +		if (prev_state & 1)
> +			event_printf("S");
> +		if (prev_state & 2)
> +			event_printf("D");
> +		if (prev_state & 4)
> +			event_printf("T");
> +		if (prev_state & 8)
> +			event_printf("t");
> +		if (prev_state & 16)
> +			event_printf("Z");
> +		if (prev_state & 32)
> +			event_printf("X");
> +		if (prev_state & 64)
> +			event_printf("x");
> +		if (prev_state & 128)
> +			event_printf("W");
> +	}
> +
> +	event_printf(") ==> %s:%d [%d]\n", next_comm, next_pid, next_prio);
> +}
> +
> +static void event_sched_migrate_task_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("task %s:%d [%d] from: %d  to: %d\n",
> +			(char *)(long)access_field(t, fc->event.data, "comm"),
> +			(int)access_field(t, fc->event.data, "pid"),
> +			(int)access_field(t, fc->event.data, "prio"),
> +			(int)access_field(t, fc->event.data, "orig_cpu"),
> +			(int)access_field(t, fc->event.data, "dest_cpu"));
> +}
> +
> +static void event_sched_process_free_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("task %s:%d [%d]\n",
> +			(char *)(long)access_field(t, fc->event.data, "comm"),
> +			(int)access_field(t, fc->event.data, "pid"),
> +			(int)access_field(t, fc->event.data, "prio"));
> +}
> +
> +static void event_sched_process_exit_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("task %s:%d [%d]\n",
> +			(char *)(long)access_field(t, fc->event.data, "comm"),
> +			(int)access_field(t, fc->event.data, "pid"),
> +			(int)access_field(t, fc->event.data, "prio"));
> +}
> +
> +static void event_sched_process_wait_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("task %s:%d [%d]\n",
> +			(char *)(long)access_field(t, fc->event.data, "comm"),
> +			(int)access_field(t, fc->event.data, "pid"),
> +			(int)access_field(t, fc->event.data, "prio"));
> +}
> +
> +static void event_sched_process_fork_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	char *parent_comm = (char *)(long)access_field(t, fc->event.data,
> +			"parent_comm");
> +	int parent_pid = access_field(t, fc->event.data, "parent_pid");
> +
> +	char *child_comm = (char *)(long)access_field(t, fc->event.data,
> +			"child_comm");
> +	int child_pid = access_field(t, fc->event.data, "child_pid");
> +
> +	event_printf("parent %s:%d  child %s:%d\n", parent_comm,
> parent_pid,
> +			child_comm, child_pid);
> +}
> +
> +static void event_sched_signal_send_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("sig: %d  task %s:%d\n",
> +			(int)access_field(t, fc->event.data, "sig"),
> +			(char *)(long)access_field(t, fc->event.data, "comm"),
> +			(int)access_field(t, fc->event.data, "pid"));
> +}
> +
> +static void event_kmalloc_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu "
> +			"gfp_flags=%lx\n",
> +			(long)access_field(t, fc->event.data, "call_site"),
> +			(void *)(long)access_field(t, fc->event.data, "ptr"),
> +			(size_t)access_field(t, fc->event.data, "bytes_req"),
> +			(size_t)access_field(t, fc->event.data, "bytes_alloc"),
> +			(long)access_field(t, fc->event.data, "gfp_flags"));
> +}
> +
> +static void event_kmem_cache_alloc_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu "
> +			"gfp_flags=%lx\n",
> +			(long)access_field(t, fc->event.data, "call_site"),
> +			(void *)(long)access_field(t, fc->event.data, "ptr"),
> +			(size_t)access_field(t, fc->event.data, "bytes_req"),
> +			(size_t)access_field(t, fc->event.data, "bytes_alloc"),
> +			(long)access_field(t, fc->event.data, "gfp_flags"));
> +}
> +
> +static void event_kmalloc_node_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu "
> +			"gfp_flags=%lx node=%d\n",
> +			(long)access_field(t, fc->event.data, "call_site"),
> +			(void *)(long)access_field(t, fc->event.data, "ptr"),
> +			(size_t)access_field(t, fc->event.data, "bytes_req"),
> +			(size_t)access_field(t, fc->event.data, "bytes_alloc"),
> +			(long)access_field(t, fc->event.data, "gfp_flags"),
> +			(int)access_field(t, fc->event.data, "node"));
> +}
> +
> +static void event_kmem_cache_alloc_node_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("call_site=%lx ptr=%p bytes_req=%zu bytes_alloc=%zu "
> +			"gfp_flags=%lx node=%d\n",
> +			(long)access_field(t, fc->event.data, "call_site"),
> +			(void *)(long)access_field(t, fc->event.data, "ptr"),
> +			(size_t)access_field(t, fc->event.data, "bytes_req"),
> +			(size_t)access_field(t, fc->event.data, "bytes_alloc"),
> +			(long)access_field(t, fc->event.data, "gfp_flags"),
> +			(int)access_field(t, fc->event.data, "node"));
> +}
> +
> +static void event_kfree_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("call_site=%lx ptr=%p\n",
> +			(long)access_field(t, fc->event.data, "call_site"),
> +			(void *)(long)access_field(t, fc->event.data, "ptr"));
> +}
> +
> +static void event_kmem_cache_free_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	event_printf("call_site=%lx ptr=%p\n",
> +			(long)access_field(t, fc->event.data, "call_site"),
> +			(void *)(long)access_field(t, fc->event.data, "ptr"));
> +}
> +
> +static void event_workqueue_insertion_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	char *thread_comm = (char *)(long)access_field(t, fc->event.data,
> +			"thread_comm");
> +	int thread_pid = access_field(t, fc->event.data, "thread_pid");
> +	ulong func = access_field(t, fc->event.data, "func");
> +
> +	event_printf("thread=%s:%d func=", thread_comm, thread_pid);
> +	sym_print(func, 1);
> +	event_printf("\n");
> +}
> +
> +static void event_workqueue_execution_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	char *thread_comm = (char *)(long)access_field(t, fc->event.data,
> +			"thread_comm");
> +	int thread_pid = access_field(t, fc->event.data, "thread_pid");
> +	ulong func = access_field(t, fc->event.data, "func");
> +
> +	event_printf("thread=%s:%d func=", thread_comm, thread_pid);
> +	sym_print(func, 1);
> +	event_printf("\n");
> +}
> +
> +static void event_workqueue_creation_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	char *thread_comm = (char *)(long)access_field(t, fc->event.data,
> +			"thread_comm");
> +	int thread_pid = access_field(t, fc->event.data, "thread_pid");
> +	int cpu = access_field(t, fc->event.data, "cpu");
> +
> +	event_printf("thread=%s:%d cpu=%d\n", thread_comm, thread_pid,
> cpu);
> +}
> +
> +static void event_workqueue_destruction_print(struct event_type *t,
> +		struct format_context *fc)
> +{
> +	char *thread_comm = (char *)(long)access_field(t, fc->event.data,
> +			"thread_comm");
> +	int thread_pid = access_field(t, fc->event.data, "thread_pid");
> +
> +	event_printf("thread=%s:%d\n", thread_comm, thread_pid);
> +}
> +
> +static void ftrace_show_trace_event_init(void)
> +{
> +#define init_trace_event(system, name)					\
> +do {									\
> +	struct event_type *t = find_event_type_by_name(#system, #name);	\
> +	if (t)								\
> +		t->printer = event_ ## name ## _print;			\
> +} while (0)
> +
> +	init_trace_event(sched, sched_kthread_stop);
> +	init_trace_event(sched, sched_kthread_stop_ret);
> +	init_trace_event(sched, sched_wait_task);
> +	init_trace_event(sched, sched_wakeup);
> +	init_trace_event(sched, sched_wakeup_new);
> +	init_trace_event(sched, sched_switch);
> +	init_trace_event(sched, sched_migrate_task);
> +	init_trace_event(sched, sched_process_free);
> +	init_trace_event(sched, sched_process_exit);
> +	init_trace_event(sched, sched_process_wait);
> +	init_trace_event(sched, sched_process_fork);
> +	init_trace_event(sched, sched_signal_send);
> +
> +	init_trace_event(kmem, kmalloc);
> +	init_trace_event(kmem, kmem_cache_alloc);
> +	init_trace_event(kmem, kmalloc_node);
> +	init_trace_event(kmem, kmem_cache_alloc_node);
> +	init_trace_event(kmem, kfree);
> +	init_trace_event(kmem, kmem_cache_free);
> +
> +	init_trace_event(workqueue, workqueue_insertion);
> +	init_trace_event(workqueue, workqueue_execution);
> +	init_trace_event(workqueue, workqueue_creation);
> +	init_trace_event(workqueue, workqueue_destruction);
> +#undef init_trace_event
> +}
> +
> diff --git a/global_data.c b/global_data.c
> index 581deb2..2c14d69 100755
> --- a/global_data.c
> +++ b/global_data.c
> @@ -103,6 +103,7 @@ struct command_table_entry linux_command_table[] =
> {
>  	{"runq",    cmd_runq,    help_runq,    REFRESH_TASK_TABLE},
>          {"search",  cmd_search,  help_search,  0},
>          {"set",     cmd_set,     help_set,     REFRESH_TASK_TABLE},
> +	{"trace",   cmd_ftrace,  help_ftrace,  0},
>          {"sig",     cmd_sig,     help_sig,     REFRESH_TASK_TABLE},
>          {"struct",  cmd_struct,  help_struct,  0},
>  	{"swap",    cmd_swap,    help_swap,    0},
> diff --git a/help.c b/help.c
> index 5f0189f..f8ddb84 100755
> --- a/help.c
> +++ b/help.c
> @@ -2899,6 +2899,39 @@ char *help_task[] = {
>  NULL               
>  };
>  
> +char *help_ftrace[] = {
> +"trace",
> +"show or dump the tracing info",
> +"[ <show [-c <cpulist>] [-f [no]<flagname>]> | <dump [-sm]
> <dest-dir>> ]",
> +"trace",
> +"    shows the current tracer and other informations.",
> +"",
> +"trace show [ -c <cpulist> ] [ -f [no]<flagename> ]",
> +"    shows all events with readability text(sorted by timestamp)",
> +"    -c: only shows specified CPUs' events.",
> +"        ex. trace show -c 1,2    - only shows cpu#1 and cpu#2 's
> events.",
> +"            trace show -c 0,2-7  - only shows cpu#0, cpu#2...cpu#7's
> events.",
> +"    -f: set or clear a flag",
> +"        available flags            default",
> +"        context_info               true",
> +"        sym_offset                 false",
> +"        sym_addr                   false",
> +"        graph_print_duration       true",
> +"        graph_print_overhead       true",
> +"        graph_print_abstime        false",
> +"        graph_print_cpu            true",
> +"        graph_print_proc           false",
> +"        graph_print_overrun        false",
> +"",
> +"trace dump [-sm] <dest-dir>",
> +"    dump ring_buffers to dest-dir. Then you can parse it",
> +"    by other tracing tools. The dirs and files are generated",
> +"    the same as debugfs/tracing.",
> +"    -m: also dump metadata of ftrace.",
> +"    -s: also dump symbols of the kernel <not implemented>.",
> +NULL
> +};
> +
>  char *help_sig[] = {
>  "sig",
>  "task signal handling",
> diff --git a/kernel.c b/kernel.c
> index 603b6e9..dd4563d 100755
> --- a/kernel.c
> +++ b/kernel.c
> @@ -132,6 +132,14 @@ kernel_init()
>  	} else 
>  		kt->cpus = 1;
>  
> +	if (symbol_exists("nr_cpu_ids"))
> +		get_symbol_data("nr_cpu_ids", sizeof(int), &kt->nr_cpu_ids);
> +	else
> +		kt->nr_cpu_ids = 1;
> +
> +	if (kt->cpus < kt->nr_cpu_ids)
> +		kt->cpus = kt->nr_cpu_ids;
> +
>  	if ((sp1 = symbol_search("__per_cpu_start")) &&
>   	    (sp2 = symbol_search("__per_cpu_end")) &&
>  	    (sp1->type == 'A' || sp1->type == 'D') && 
> diff --git a/main.c b/main.c
> index 5d79eef..9831539 100755
> --- a/main.c
> +++ b/main.c
> @@ -516,6 +516,7 @@ main_loop(void)
>  			net_init();
>  			dev_init();
>  			machdep_init(POST_INIT);
> +			ftrace_init();
>  		}
>  	} else
>  		SIGACTION(SIGINT, restart, &pc->sigaction, NULL);




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