[Crash-utility] Speed up list/tree '-s' output.
Dave Anderson
anderson at redhat.com
Wed Aug 24 20:26:19 UTC 2016
----- Original Message -----
> Hi Dave,
>
> here is patch with arguments instead of static variables:
Looks good, thanks!
I'm still working with the symtab.c patch, because as it turns out, it
can obviate the need for ANON_MEMBER_OFFSET_INIT() in most cases, which
will speed up session initialization. Pretty nifty...
Thanks,
Dave
>
> --- gdb-7.6.orig/gdb/symtab.c 2016-08-18 09:06:33.000000000 +0300
> +++ gdb-7.6/gdb/symtab.c 2016-08-24 08:40:45.700772046 +0300
> @@ -5122,7 +5122,7 @@
> #define GDB_COMMON
> #include "../../defs.h"
>
> -static void get_member_data(struct gnu_request *, struct type *);
> +static void get_member_data(struct gnu_request *, struct type *, long,
> char);
> static void dump_enum(struct type *, struct gnu_request *);
> static void eval_enum(struct type *, struct gnu_request *);
> static void gdb_get_line_number(struct gnu_request *);
> @@ -5327,7 +5327,7 @@
> req->typecode = TYPE_CODE(sym->type);
> req->length = TYPE_LENGTH(sym->type);
> if (req->member)
> - get_member_data(req, sym->type);
> + get_member_data(req, sym->type, 0, 1);
>
> if (TYPE_CODE(sym->type) == TYPE_CODE_ENUM) {
> if (req->flags & GNU_PRINT_ENUMERATORS)
> @@ -5397,7 +5397,7 @@
> }
>
> if (req->member)
> - get_member_data(req, type);
> + get_member_data(req, type, 0, 1);
>
> break;
>
> @@ -5480,7 +5480,7 @@
> * member field, and when found, return its relevant data.
> */
> static void
> -get_member_data(struct gnu_request *req, struct type *type)
> +get_member_data(struct gnu_request *req, struct type *type, long offset,
> char is_first)
> {
> register short i;
> struct field *nextfield;
> @@ -5492,7 +5492,7 @@
> nfields = TYPE_MAIN_TYPE(type)->nfields;
> nextfield = TYPE_MAIN_TYPE(type)->flds_bnds.fields;
>
> - if (nfields == 0) {
> + if (nfields == 0 && is_first /* The first call */) {
> struct type *newtype;
> newtype = lookup_transparent_type(req->name);
> if (newtype) {
> @@ -5505,13 +5505,18 @@
>
> for (i = 0; i < nfields; i++) {
> if (STREQ(req->member, nextfield->name)) {
> - req->member_offset = nextfield->loc.bitpos;
> + req->member_offset = offset + nextfield->loc.bitpos;
> req->member_length = TYPE_LENGTH(nextfield->type);
> req->member_typecode = TYPE_CODE(nextfield->type);
> if ((req->member_typecode == TYPE_CODE_TYPEDEF) &&
> (typedef_type = check_typedef(nextfield->type)))
> req->member_length = TYPE_LENGTH(typedef_type);
> return;
> + } else if (*nextfield->name == 0) { /* Anonymous struct/union */
> + get_member_data(req, nextfield->type,
> + offset + nextfield->loc.bitpos, 0);
> + if (req->member_offset != -1)
> + return;
> }
> nextfield++;
> }
> @@ -5706,7 +5711,7 @@
> }
>
> if (req->member)
> - get_member_data(req, type);
> + get_member_data(req, type, 0, 1);
>
> do_cleanups (old_chain);
> }
>
> Thanks,
> Alexandr
> ________________________________________
> From: crash-utility-bounces at redhat.com <crash-utility-bounces at redhat.com> on
> behalf of Dave Anderson <anderson at redhat.com>
> Sent: Tuesday, August 23, 2016 23:17
> To: Discussion list for crash utility usage, maintenance and development
> Subject: Re: [Crash-utility] Speed up list/tree '-s' output.
>
> Hi Alexandr,
>
> I'm still testing and sanity-checking the symtab.c patch given that it's
> modifying such a commonly-called function. Interestingly enough, it's
> actually uncovered a bug with the current determination of the page.list
> members, which I found by saving the output of "help -o" into a file,
> both without and then with your patch, into /tmp/old and /tmp/new, and
> then diff'ed the two files:
>
> # diff /tmp/old /tmp/new
> 221,223c221,223
> < page_list: -1
> < page_list_next: -1
> < page_list_prev: -1
> ---
> > page_list: 32
> > page_list_next: 32
> > page_list_prev: 40
> #
>
> Fortunately those fields aren't used by the crash code for more recent
> kernels, which have gone crazy with the anonymous structures in the page
> structure. But anyway, that was a good catch by your patch.
>
> On the other hand, I don't like the use of the deep and offset static
> variables, because there's always the remote possibility that a
> CTRL-C or other function failure may happen while they are set, and
> then leave them in a bogus state. So I would rather they get passed as
> arguments.
>
> Thanks,
> Dave
>
>
>
> ----- Original Message -----
> > Hi Dave,
> >
> > here is updated patch for gdb/symtab.c:
> >
> > --- gdb-7.6.orig/gdb/symtab.c 2016-08-18 09:06:33.000000000 +0300
> > +++ gdb-7.6/gdb/symtab.c 2016-08-23 14:28:45.456510348 +0300
> > @@ -5486,13 +5486,15 @@
> > struct field *nextfield;
> > short nfields;
> > struct type *typedef_type;
> > + static int deep = 0;
> > + static long offset = 0;
> >
> > req->member_offset = -1;
> >
> > nfields = TYPE_MAIN_TYPE(type)->nfields;
> > nextfield = TYPE_MAIN_TYPE(type)->flds_bnds.fields;
> >
> > - if (nfields == 0) {
> > + if (nfields == 0 && deep == 0 /* The first call */) {
> > struct type *newtype;
> > newtype = lookup_transparent_type(req->name);
> > if (newtype) {
> > @@ -5505,13 +5507,21 @@
> >
> > for (i = 0; i < nfields; i++) {
> > if (STREQ(req->member, nextfield->name)) {
> > - req->member_offset = nextfield->loc.bitpos;
> > + req->member_offset = offset + nextfield->loc.bitpos;
> > req->member_length = TYPE_LENGTH(nextfield->type);
> > req->member_typecode = TYPE_CODE(nextfield->type);
> > if ((req->member_typecode == TYPE_CODE_TYPEDEF) &&
> > (typedef_type = check_typedef(nextfield->type)))
> > req->member_length =
> > TYPE_LENGTH(typedef_type);
> > return;
> > + } else if (*nextfield->name == 0) { /* Anonymous struct/union
> > */
> > + deep++;
> > + offset += nextfield->loc.bitpos;
> > + get_member_data(req, nextfield->type);
> > + offset -= nextfield->loc.bitpos;
> > + deep--;
> > + if (req->member_offset != -1)
> > + return;
> > }
> > nextfield++;
> > }
> > @@ -5705,7 +5715,7 @@
> > req->target_length = target_type->length;
> > }
> >
> > - if (req->member)
> > + if (req->member)
> > get_member_data(req, type);
> >
> > do_cleanups (old_chain);
> >
> > The patch for crash tool can be found on github:
> > https://raw.githubusercontent.com/hziSot/crash-patches/41abc6f9c91c2a602973ff9564234395deadb80e/crash_speed_up_tree_list.patch
> >
> > Thanks,
> > Alexandr
> >
> > --
> > Crash-utility mailing list
> > Crash-utility at redhat.com
> > https://www.redhat.com/mailman/listinfo/crash-utility
> >
>
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