[libvirt] [PATCH] Add a systemtap script for watching QEMU monitor interactions
Daniel P. Berrange
berrange at redhat.com
Mon Oct 24 14:37:04 UTC 2011
From: "Daniel P. Berrange" <berrange at redhat.com>
This change adds some systemtap/dtrace probes to the QEMU monitor
client code. In particular it allows watching of all operations
for a VM
* examples/systemtap/qemu-monitor.stp: Watch all monitor commands
* src/Makefile.am: Passing libdir/bindir/sbindir to dtrace2systemtap.pl
* src/dtrace2systemtap.pl: Accept libdir/bindir/sbindir as args
and look for '# binary:' comment to mark probes against libvirtd
vs libvirt.so
* src/qemu/qemu_monitor.c, src/qemu/qemu_monitor_json.c,
src/qemu/qemu_monitor_text.c: Add probes for key functions
---
examples/systemtap/qemu-monitor.stp | 81 +++++++++++++++++++++++++++++++++++
src/Makefile.am | 2 +-
src/dtrace2systemtap.pl | 15 ++++++-
src/probes.d | 20 +++++++++
src/qemu/qemu_monitor.c | 31 ++++++++++++-
src/qemu/qemu_monitor_json.c | 4 ++
src/qemu/qemu_monitor_text.c | 3 +
7 files changed, 150 insertions(+), 6 deletions(-)
create mode 100644 examples/systemtap/qemu-monitor.stp
diff --git a/examples/systemtap/qemu-monitor.stp b/examples/systemtap/qemu-monitor.stp
new file mode 100644
index 0000000..647eacc
--- /dev/null
+++ b/examples/systemtap/qemu-monitor.stp
@@ -0,0 +1,81 @@
+#!/usr/bin/stap
+#
+# Copyright (C) 2011 Red Hat, Inc.
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+#
+# Author: Daniel P. Berrange <berrange at redhat.com>
+#
+# This script will monitor all messages sent/received between libvirt
+# and the QEMU monitor
+#
+# stap qemu-monitor.stp
+# 0.000 begin
+# 3.848 ! 0x7f2dc00017b0 {"timestamp": {"seconds": 1319466931, "microseconds": 187755}, "event": "SHUTDOWN"}
+# 5.773 > 0x7f2dc0007960 {"execute":"qmp_capabilities","id":"libvirt-1"}
+# 5.774 < 0x7f2dc0007960 {"return": {}, "id": "libvirt-1"}
+# 5.774 > 0x7f2dc0007960 {"execute":"query-commands","id":"libvirt-2"}
+# 5.777 < 0x7f2dc0007960 {"return": [{"name": "quit"}, {"name": ....snip....
+# 5.777 > 0x7f2dc0007960 {"execute":"query-chardev","id":"libvirt-3"}
+# 5.778 < 0x7f2dc0007960 {"return": [{"filename": ....snip....
+# 5.779 > 0x7f2dc0007960 {"execute":"query-cpus","id":"libvirt-4"}
+# 5.780 < 0x7f2dc0007960 {"return": [{"current": true, "CPU": 0, "pc": 1048560, "halted": false, "thread_id": 13299}], "id": "libvirt-4"}
+# 5.780 > 0x7f2dc0007960 {"execute":"set_password","arguments":{"protocol":"vnc","password":"123456","connected":"keep"},"id":"libvirt-5"}
+# 5.782 < 0x7f2dc0007960 {"return": {}, "id": "libvirt-5"}
+# 5.782 > 0x7f2dc0007960 {"execute":"expire_password","arguments":{"protocol":"vnc","time":"never"},"id":"libvirt-6"}
+# 5.783 < 0x7f2dc0007960 {"return": {}, "id": "libvirt-6"}
+# 5.783 > 0x7f2dc0007960 {"execute":"balloon","arguments":{"value":224395264},"id":"libvirt-7"}
+# 5.785 < 0x7f2dc0007960 {"return": {}, "id": "libvirt-7"}
+# 5.785 > 0x7f2dc0007960 {"execute":"cont","id":"libvirt-8"}
+# 5.789 ! 0x7f2dc0007960 {"timestamp": {"seconds": 1319466933, "microseconds": 129980}, "event": "RESUME"}
+# 5.789 < 0x7f2dc0007960 {"return": {}, "id": "libvirt-8"}
+# 7.537 ! 0x7f2dc0007960 {"timestamp": {"seconds": 1319466934, "microseconds": 881214}, "event": "SHUTDOWN"}
+#
+
+
+global start
+
+# Print a string, with a timestamp relative to the start of the script
+function print_ts(msg)
+{
+ now = gettimeofday_ns() / (1000*1000)
+ delta = (now - start)
+
+ printf("%3d.%03d %s\n", (delta / 1000), (delta % 1000), msg);
+}
+
+
+# Just so we know the script is now running
+probe begin {
+ start = gettimeofday_ns() / (1000*1000)
+ print_ts("begin")
+}
+
+probe libvirt.qemu.monitor_send_msg {
+ if (fd != -1) {
+ print_ts(sprintf("> %p %s (fd=%d)", mon, substr(msg, 0, strlen(msg)-2), fd));
+ } else {
+ print_ts(sprintf("> %p %s", mon, substr(msg, 0, strlen(msg)-2)));
+ }
+}
+
+probe libvirt.qemu.monitor_recv_reply {
+ print_ts(sprintf("< %p %s", mon, reply));
+}
+
+probe libvirt.qemu.monitor_recv_event {
+ print_ts(sprintf("! %p %s", mon, event));
+}
+
diff --git a/src/Makefile.am b/src/Makefile.am
index 2555f81..81ec730 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1288,7 +1288,7 @@ libvirt_functions.stp: $(RPC_PROBE_FILES) $(srcdir)/rpc/gensystemtap.pl
$(AM_V_GEN)perl -w $(srcdir)/rpc/gensystemtap.pl $(RPC_PROBE_FILES) > $@
libvirt_probes.stp: probes.d $(srcdir)/dtrace2systemtap.pl
- $(AM_V_GEN)perl -w $(srcdir)/dtrace2systemtap.pl $< > $@
+ $(AM_V_GEN)perl -w $(srcdir)/dtrace2systemtap.pl $(bindir) $(sbindir) $(libdir) $< > $@
CLEANFILES += probes.h probes.o libvirt_functions.stp libvirt_probes.stp
endif
diff --git a/src/dtrace2systemtap.pl b/src/dtrace2systemtap.pl
index fab066b..b577eac 100755
--- a/src/dtrace2systemtap.pl
+++ b/src/dtrace2systemtap.pl
@@ -31,6 +31,10 @@ my $file;
my @files;
my %files;
+my $bindir = shift @ARGV;
+my $sbindir = shift @ARGV;
+my $libdir = shift @ARGV;
+
my $probe;
my $args;
@@ -47,6 +51,8 @@ while (<>) {
$files{$file} = { prefix => undef, probes => [] };
} elsif (m,^\s*\#\s*prefix:\s*(\S+)\s*$,) {
$files{$file}->{prefix} = $1;
+ } elsif (m,^\s*\#\s*binary:\s*(\S+)\s*$,) {
+ $files{$file}->{binary} = $1;
} else {
if (m,\s*probe\s+([a-zA-Z0-9_]+)\((.*?)(\);)?$,) {
$probe = $1;
@@ -66,7 +72,7 @@ while (<>) {
die "unexpected data $_ on line $.";
}
} else {
- die "unexpected data $_ on line $.";
+ #die "unexpected data $_ on line $.";
}
}
}
@@ -84,7 +90,12 @@ foreach my $file (@files) {
my $pname = $name;
$pname =~ s/${prefix}_/libvirt.$prefix./;
- print "probe $pname = process(\"libvirt.so\").mark(\"$name\") {\n";
+ my $binary = "$libdir/libvirt.so";
+ if (exists $files{$file}->{binary}) {
+ $binary = $sbindir . "/" . $files{$file}->{binary};
+ }
+
+ print "probe $pname = process(\"$binary\").mark(\"$name\") {\n";
my @args = split /,/, $args;
for (my $i = 0 ; $i <= $#args ; $i++) {
diff --git a/src/probes.d b/src/probes.d
index 6d95c84..7f66ac0 100644
--- a/src/probes.d
+++ b/src/probes.d
@@ -69,4 +69,24 @@ provider libvirt {
probe rpc_tls_session_handshake_pass(void *sess);
probe rpc_tls_session_handshake_fail(void *sess);
+
+ # file: src/qemu/qemu_monitor.c
+ # prefix: qemu
+ # binary: libvirtd
+ # Monitor lifecycle
+ probe qemu_monitor_new(void *mon, int refs, int fd);
+ probe qemu_monitor_ref(void *mon, int refs);
+ probe qemu_monitor_unref(void *mon, int refs);
+ probe qemu_monitor_close(void *monm, int refs);
+
+ # High level monitor message processing
+ probe qemu_monitor_send_msg(void *mon, const char *msg, int fd);
+ probe qemu_monitor_recv_reply(void *mon, const char *reply);
+ probe qemu_monitor_recv_event(void *mon, const char *event);
+
+ # Low level monitor I/O processing
+ probe qemu_monitor_io_process(void *mon, const char *buf, unsigned int len);
+ probe qemu_monitor_io_read(void *mon, const char *buf, unsigned int len, int ret, int errno);
+ probe qemu_monitor_io_write(void *mon, const char *buf, unsigned int len, int ret, int errno);
+ probe qemu_monitor_io_send_fd(void *mon, int fd, int ret, int errno);
};
diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c
index 182e63d..75429fa 100644
--- a/src/qemu/qemu_monitor.c
+++ b/src/qemu/qemu_monitor.c
@@ -183,6 +183,8 @@ static void qemuMonitorFree(qemuMonitorPtr mon)
int qemuMonitorRef(qemuMonitorPtr mon)
{
mon->refs++;
+ PROBE(QEMU_MONITOR_UNREF,
+ "mon=%p refs=%d", mon, mon->refs);
return mon->refs;
}
@@ -190,6 +192,8 @@ int qemuMonitorUnref(qemuMonitorPtr mon)
{
mon->refs--;
+ PROBE(QEMU_MONITOR_UNREF,
+ "mon=%p refs=%d", mon, mon->refs);
if (mon->refs == 0) {
qemuMonitorUnlock(mon);
qemuMonitorFree(mon);
@@ -305,6 +309,9 @@ qemuMonitorIOProcess(qemuMonitorPtr mon)
# endif
#endif
+ PROBE(QEMU_MONITOR_IO_PROCESS,
+ "mon=%p buf=%s len=%zu", mon, mon->buffer, mon->bufferOffset);
+
if (mon->json)
len = qemuMonitorJSONIOProcess(mon,
mon->buffer, mon->bufferOffset,
@@ -403,6 +410,18 @@ qemuMonitorIOWrite(qemuMonitorPtr mon)
mon->msg->txLength - mon->msg->txOffset,
mon->msg->txFD);
+ PROBE(QEMU_MONITOR_IO_WRITE,
+ "mon=%p buf=%s len=%d ret=%d errno=%d",
+ mon,
+ mon->msg->txBuffer + mon->msg->txOffset,
+ mon->msg->txLength - mon->msg->txOffset,
+ done, errno);
+
+ if (mon->msg->txFD != -1)
+ PROBE(QEMU_MONITOR_IO_SEND_FD,
+ "mon=%p fd=%d ret=%d errno=%d",
+ mon, mon->msg->txFD, done, errno);
+
if (done < 0) {
if (errno == EAGAIN)
return 0;
@@ -696,7 +715,9 @@ qemuMonitorOpen(virDomainObjPtr vm,
}
qemuMonitorRef(mon);
- VIR_DEBUG("New mon %p fd =%d watch=%d", mon, mon->fd, mon->watch);
+ PROBE(QEMU_MONITOR_NEW,
+ "mon=%p refs=%d fd=%d",
+ mon, mon->refs, mon->fd);
qemuMonitorUnlock(mon);
return mon;
@@ -719,9 +740,9 @@ void qemuMonitorClose(qemuMonitorPtr mon)
if (!mon)
return;
- VIR_DEBUG("mon=%p", mon);
-
qemuMonitorLock(mon);
+ PROBE(QEMU_MONITOR_CLOSE,
+ "mon=%p refs=%d", mon, mon->refs);
if (mon->fd >= 0) {
if (mon->watch)
@@ -762,6 +783,10 @@ int qemuMonitorSend(qemuMonitorPtr mon,
mon->msg = msg;
qemuMonitorUpdateWatch(mon);
+ PROBE(QEMU_MONITOR_SEND_MSG,
+ "mon=%p msg=%s fd=%d",
+ mon, mon->msg->txBuffer, mon->msg->txFD);
+
while (!mon->msg->finished) {
if (virCondWait(&mon->notify, &mon->lock) < 0) {
qemuReportError(VIR_ERR_INTERNAL_ERROR, "%s",
diff --git a/src/qemu/qemu_monitor_json.c b/src/qemu/qemu_monitor_json.c
index cd8f1e5..2c4aee5 100644
--- a/src/qemu/qemu_monitor_json.c
+++ b/src/qemu/qemu_monitor_json.c
@@ -126,9 +126,13 @@ qemuMonitorJSONIOProcessLine(qemuMonitorPtr mon,
if (virJSONValueObjectHasKey(obj, "QMP") == 1) {
ret = 0;
} else if (virJSONValueObjectHasKey(obj, "event") == 1) {
+ PROBE(QEMU_MONITOR_RECV_EVENT,
+ "mon=%p event=%s", mon, line);
ret = qemuMonitorJSONIOProcessEvent(mon, obj);
} else if (virJSONValueObjectHasKey(obj, "error") == 1 ||
virJSONValueObjectHasKey(obj, "return") == 1) {
+ PROBE(QEMU_MONITOR_RECV_REPLY,
+ "mon=%p reply=%s", mon, line);
if (msg) {
msg->rxObject = obj;
msg->finished = 1;
diff --git a/src/qemu/qemu_monitor_text.c b/src/qemu/qemu_monitor_text.c
index 4774df9..c652321 100644
--- a/src/qemu/qemu_monitor_text.c
+++ b/src/qemu/qemu_monitor_text.c
@@ -198,6 +198,9 @@ int qemuMonitorTextIOProcess(qemuMonitorPtr mon ATTRIBUTE_UNUSED,
VIR_DEBUG("Finished 0 byte reply");
#endif
}
+ PROBE(QEMU_MONITOR_RECV_REPLY,
+ "mon=%p reply=%s",
+ mon, msg->rxBuffer);
msg->finished = 1;
used += end - (data + used);
used += strlen(BASIC_PROMPT);
--
1.7.6.4
More information about the libvir-list
mailing list