Re: [tip:perfcounters/core] perf trace: Sample the CPU too

Frederic Weisbecker
2009-09-03T01:52:44Z

On Wed, Sep 02, 2009 at 11:54:56PM +0200, Ingo Molnar wrote:
>
> * Frederic Weisbecker <fweisbec@gmail.com> wrote:
>
> > On Wed, Sep 02, 2009 at 07:31:51PM +0000, tip-bot for Ingo Molnar wrote:
> > > Commit-ID: cd6feeeafddbef6abfe4d90fb26e42fd844d34ed
> > > Gitweb: http://git.kernel.org/tip/cd6feeeafddbef6abfe4d90fb26e42fd844d34ed
> > > Author: Ingo Molnar <mingo@elte.hu>
> > > AuthorDate: Wed, 2 Sep 2009 20:20:38 +0200
> > > Committer: Ingo Molnar <mingo@elte.hu>
> > > CommitDate: Wed, 2 Sep 2009 21:28:50 +0200
> > >
> > > perf trace: Sample the CPU too
> > >
> > > Sample, record, parse and print the CPU field - it had all zeroes before.
> > >
> > > Before (watch the second column, the CPU values):
> > >
> > > perf-32685 [000] 0.000000: sched_wakeup_new: task perf:32686 [120] success=1 [011]
> > > perf-32685 [000] 0.000000: sched_migrate_task: task perf:32685 [120] from: 1 to: 11
> > > perf-32685 [000] 0.000000: sched_process_fork: parent perf:32685 child perf:32686
> > > true-32686 [000] 0.000000: sched_wakeup: task migration/11:25 [0] success=1 [011]
> > > true-32686 [000] 0.000000: sched_wakeup: task distccd:12793 [125] success=1 [015]
> > > true-32686 [000] 0.000000: sched_wakeup: task distccd:12793 [125] success=1 [015]
> > > perf-32685 [000] 0.000000: sched_switch: task perf:32685 [120] (S) ==> swapper:0 [140]
> > > true-32686 [000] 0.000000: sched_switch: task perf:32686 [120] (R) ==> migration/11:25 [0]
> > > true-32686 [000] 0.000000: sched_switch: task perf:32686 [120] (R) ==> distccd:12793 [125]
> > > true-32686 [000] 0.000000: sched_switch: task true:32686 [120] (R) ==> distccd:12793 [125]
> > > true-32686 [000] 0.000000: sched_process_exit: task true:32686 [120]
> > > true-32686 [000] 0.000000: sched_stat_wait: task: distccd:12793 wait: 6767985949080 [ns]
> > > true-32686 [000] 0.000000: sched_stat_wait: task: distccd:12793 wait: 6767986139446 [ns]
> > > true-32686 [000] 0.000000: sched_stat_sleep: task: distccd:12793 sleep: 132844 [ns]
> > > true-32686 [000] 0.000000: sched_stat_sleep: task: distccd:12793 sleep: 131724 [ns]
> > >
> > > After:
> > >
> > > perf-32685 [001] 0.000000: sched_wakeup_new: task perf:32686 [120] success=1 [011]
> > > perf-32685 [001] 0.000000: sched_migrate_task: task perf:32685 [120] from: 1 to: 11
> > > perf-32685 [001] 0.000000: sched_process_fork: parent perf:32685 child perf:32686
> > > true-32686 [011] 0.000000: sched_wakeup: task migration/11:25 [0] success=1 [011]
> > > true-32686 [015] 0.000000: sched_wakeup: task distccd:12793 [125] success=1 [015]
> > > true-32686 [015] 0.000000: sched_wakeup: task distccd:12793 [125] success=1 [015]
> > > perf-32685 [001] 0.000000: sched_switch: task perf:32685 [120] (S) ==> swapper:0 [140]
> > > true-32686 [011] 0.000000: sched_switch: task perf:32686 [120] (R) ==> migration/11:25 [0]
> > > true-32686 [015] 0.000000: sched_switch: task perf:32686 [120] (R) ==> distccd:12793 [125]
> > > true-32686 [015] 0.000000: sched_switch: task true:32686 [120] (R) ==> distccd:12793 [125]
> > > true-32686 [015] 0.000000: sched_process_exit: task true:32686 [120]
> > > true-32686 [015] 0.000000: sched_stat_wait: task: distccd:12793 wait: 6767985949080 [ns]
> > > true-32686 [015] 0.000000: sched_stat_wait: task: distccd:12793 wait: 6767986139446 [ns]
> > > true-32686 [015] 0.000000: sched_stat_sleep: task: distccd:12793 sleep: 132844 [ns]
> > > true-32686 [015] 0.000000: sched_stat_sleep: task: distccd:12793 sleep: 131724 [ns]
> > >
> > > So we can now see how this workload migrated between CPUs.
> > >
> > > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> > > Cc: Paul Mackerras <paulus@samba.org>
> > > Cc: Frederic Weisbecker <fweisbec@gmail.com>
> > > Cc: Li Zefan <lizf@cn.fujitsu.com>
> > > Cc: Mike Galbraith <efault@gmx.de>
> > > Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> > > LKML-Reference: <new-submission>
> > > Signed-off-by: Ingo Molnar <mingo@elte.hu>
> > >
> > >
> > > ---
> > > tools/perf/builtin-record.c | 4 +++-
> > > tools/perf/builtin-trace.c | 9 ++++++++-
> > > 2 files changed, 11 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> > > index add514d..ff93f8e 100644
> > > --- a/tools/perf/builtin-record.c
> > > +++ b/tools/perf/builtin-record.c
> > > @@ -403,8 +403,10 @@ static void create_counter(int counter, int cpu, pid_t pid)
> > > if (call_graph)
> > > attr->sample_type |= PERF_SAMPLE_CALLCHAIN;
> > >
> > > - if (raw_samples)
> > > + if (raw_samples) {
> > > attr->sample_type |= PERF_SAMPLE_RAW;
> > > + attr->sample_type |= PERF_SAMPLE_CPU;
> > > + }
> > >
> > > attr->mmap = track;
> > > attr->comm = track;
> > > diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
> > > index 8247fd0..bbe4c44 100644
> > > --- a/tools/perf/builtin-trace.c
> > > +++ b/tools/perf/builtin-trace.c
> > > @@ -58,12 +58,19 @@ process_sample_event(event_t *event, unsigned long offset, unsigned long head)
> > > struct dso *dso = NULL;
> > > struct thread *thread;
> > > u64 ip = event->ip.ip;
> > > + u32 cpu = -1;
> > > u64 period = 1;
> > > void *more_data = event->ip.__more_data;
> > > int cpumode;
> > >
> > > thread = threads__findnew(event->ip.pid, &threads, &last_match);
> > >
> > > + if (sample_type & PERF_SAMPLE_CPU) {
> > > + cpu = *(u32 *)more_data;
> > > + more_data += sizeof(u32);
> > > + more_data += sizeof(u32); /* reserved */
> > > + }
> > > +
> >
> >
> > Cool, I've searched an easy way to have the cpu and I wasn't even
> > aware of this type of event :-)
> >
> >
> > What about the timestamp now? I guess a specific field should be
> > filled for tracepoint raw samples. Or may be for every raw
> > samples?
>
> how about:
>
> * { u64 time; } && PERF_SAMPLE_TIME
>
> ?
>
> Here's the full list of sample options btw:
>
> /*
> * struct {
> * struct perf_event_header header;
> *
> * { u64 ip; } && PERF_SAMPLE_IP
> * { u32 pid, tid; } && PERF_SAMPLE_TID
> * { u64 time; } && PERF_SAMPLE_TIME
> * { u64 addr; } && PERF_SAMPLE_ADDR
> * { u64 id; } && PERF_SAMPLE_ID
> * { u64 stream_id;} && PERF_SAMPLE_STREAM_ID
> * { u32 cpu, res; } && PERF_SAMPLE_CPU
> * { u64 period; } && PERF_SAMPLE_PERIOD
> *
> * { struct read_format values; } && PERF_SAMPLE_READ
> *
> * { u64 nr,
> * u64 ips[nr]; } && PERF_SAMPLE_CALLCHAIN
> *
>
> Ingo

Looks pretty good!

I'll implement that, thanks.