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perf kvm: Fix bug resolving guest kernel syms 

Guest kernel symbols are not resolved despite passing the information
needed to resolve them. e.g.,

perf kvm --guest --guestmount=/tmp/guest-mount record -a -- sleep 1
perf kvm --guest --guestmount=/tmp/guest-mount report --stdio

    36.55%  [guest/11399]  [unknown]         [g] 0xffffffff81600bc8
    33.19%  [guest/10474]  [unknown]         [g] 0x00000000c0116e00
    30.26%  [guest/11094]  [unknown]         [g] 0xffffffff8100a288
    43.69%  [guest/10474]  [unknown]         [g] 0x00000000c0103d90
    37.38%  [guest/11399]  [unknown]         [g] 0xffffffff81600bc8
    12.24%  [guest/11094]  [unknown]         [g] 0xffffffff810aa91d
     6.69%  [guest/11094]  [unknown]         [u] 0x00007fa784d721c3

which is just pathetic.

After a maddening 2 days sifting through perf minutia I found it --
id_hdr_size is not initialized for guest machines. This shows up on the
report side as random garbage for the cpu and timestamp, e.g.,

29816 7310572949125804849 0x1ac0 [0x50]: PERF_RECORD_MMAP ...

That messes up the sample sorting such that synthesized guest maps are
processed last.

With this patch you get a much more helpful report:

  12.11%  [guest/11399]  [guest.kernel.kallsyms.11399]  [g] irqtime_account_process_tick
  10.58%  [guest/11399]  [guest.kernel.kallsyms.11399]  [g] run_timer_softirq
   6.95%  [guest/11094]  [guest.kernel.kallsyms.11094]  [g] printk_needs_cpu
   6.50%  [guest/11094]  [guest.kernel.kallsyms.11094]  [g] do_timer
   6.45%  [guest/11399]  [guest.kernel.kallsyms.11399]  [g] idle_balance
   4.90%  [guest/11094]  [guest.kernel.kallsyms.11094]  [g] native_read_tsc
    ...

v2:
- changed rbtree walk to use rb_first per Namhyung's suggestion

Tested-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1342826756-64663-5-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
David Ahern 2012-07-20 17:25:49 -06:00 committed by Arnaldo Carvalho de Melo
parent 7c0f4a4113
commit adb5d2a487
3 changed files with 15 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
tools/perf/util/map.c
View File

@ -729,3 +729,16 @@ char *machine__mmap_name(struct machine *self, char *bf, size_t size)
return bf;
}
void machines__set_id_hdr_size(struct rb_root *machines, u16 id_hdr_size)
{
struct rb_node *node;
struct machine *machine;
for (node = rb_first(machines); node; node = rb_next(node)) {
machine = rb_entry(node, struct machine, rb_node);
machine->id_hdr_size = id_hdr_size;
}
return;
}

1
tools/perf/util/map.h
View File

@ -151,6 +151,7 @@ struct machine *machines__add(struct rb_root *self, pid_t pid,
struct machine *machines__find_host(struct rb_root *self);
struct machine *machines__find(struct rb_root *self, pid_t pid);
struct machine *machines__findnew(struct rb_root *self, pid_t pid);
void machines__set_id_hdr_size(struct rb_root *self, u16 id_hdr_size);
char *machine__mmap_name(struct machine *self, char *bf, size_t size);
int machine__init(struct machine *self, const char *root_dir, pid_t pid);
void machine__exit(struct machine *self);

1
tools/perf/util/session.c
View File

@ -87,6 +87,7 @@ void perf_session__update_sample_type(struct perf_session *self)
self->sample_id_all = perf_evlist__sample_id_all(self->evlist);
self->id_hdr_size = perf_evlist__id_hdr_size(self->evlist);
self->host_machine.id_hdr_size = self->id_hdr_size;
machines__set_id_hdr_size(&self->machines, self->id_hdr_size);
}
int perf_session__create_kernel_maps(struct perf_session *self)