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Date: Thu, 22 Sep 2016 10:34:57 +0900
From: Namhyung Kim <namhyung@...nel.org>
To: Stephane Eranian <eranian@...gle.com>
CC: Jiri Olsa <jolsa@...hat.com>,
Arnaldo Carvalho de Melo <acme@...hat.com>,
LKML <linux-kernel@...r.kernel.org>,
Peter Zijlstra <peterz@...radead.org>,
"mingo@...e.hu" <mingo@...e.hu>,
"ak@...ux.intel.com" <ak@...ux.intel.com>,
Vince Weaver <vincent.weaver@...ne.edu>,
Arnaldo Carvalho de Melo <acme@...nel.org>
Subject: Re: [BUG] perf report --pid not reporting correctly
On Wed, Sep 21, 2016 at 01:18:52PM -0700, Stephane Eranian wrote:
> On Wed, Sep 21, 2016 at 9:34 AM, Jiri Olsa <jolsa@...hat.com> wrote:
> > On Wed, Sep 21, 2016 at 12:37:53PM -0300, Arnaldo Carvalho de Melo wrote:
> >> Em Tue, Sep 20, 2016 at 06:29:59PM -0700, Stephane Eranian escreveu:
> >> > Hi Arnaldo,
> >> >
> >> > I ran into an issue trying to use the --pid filtering option of perf report.
> >> >
> >> > I do a system-wide collection and then I want to narrow down the
> >> > reporting to a specific process:
> >> >
> >> > $ perf record -a -e cycles:pp sleep 10
> >> > $ perf report --sort cpu,comm --pid X
> >> >
> >> > Where X is a process sampled during the run (easy to catch with perf report -D)
> >> > If you do it this way, it works, but if you do:
> >> >
> >> > $ perf report --sort cpu --pid X
> >> >
> >> > Then you get an empty output.
> >> >
> >> > I suspect it has to do with the way hist entries are added to the
> >> > histogram and aggregated. If the first event for a sort criteria is
> >> > not coming from pid X, it will
> >> > still be added in the histogram. if pid X aggregates to the same
> >> > sample criteria, then you will lose the pid information. And then
> >> > later when you try to apply the filter,
> >> > it will mark the hist entry as FILTERED because it does not have a matching pid
> >> > and nothing will be printed.
> >> > I suspect you want to apply the filtering upfront for pid. It will
> >> > only add to the histograms matching samples. It changes the
> >> > percentages you will see. They will
> >> > only report the breakdown for the pid.
> >> >
> >> > I have a quick hack to do upfront filtering which does something as
> >> > follows but I am not sure this is the correct way of doing this.
> >> >
> >> > Let me know what you think.
> >>
> >> From a first look I think this makes sense, i.e. we should do the first
> >> round of filtering, one that trows away stuff, for things in the command
> >> line, when creating the histogram entries.
> >>
> >> Later, as we have now, we can apply further filters for non-collapsed
> >> fields of hist_entry.
> >>
> >> Jiri, Namhyung, are you ok with this?
> >
> > Stephan is correct with analysis, but I think we need to add both non/filtered
> > entries in, because we provide that 'F' key for non/filtered counts switch in tui
> >
> > how about something like below
> >
> > thanks,
> > jirka
> >
> > ---
> > diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
> > index b02992efb513..659e0357be68 100644
> > --- a/tools/perf/util/hist.c
> > +++ b/tools/perf/util/hist.c
> > @@ -536,6 +536,14 @@ static struct hist_entry *hists__findnew_entry(struct hists *hists,
> > map__put(he->ms.map);
> > he->ms.map = map__get(entry->ms.map);
> > }
> > +
> > + /*
> > + * We have at least one entry in which is not
> > + * filtered, we want to display the entry.
> > + */
> > + if (he->filtered && !entry->filtered)
> > + he->filtered = 0;
> > +
> > goto out;
> > }
> >
> Works for me. So with this approach the % shown with --pid still
> represents % of total samples and not just for that pid.
> I think this is okay as long as this is documented and understood by users.
> Thanks.
I think we should show correct value depending on the --percentage
option. I wrote a patch to implement it by addding a
total_early_filtered_period stat to hists. Following is the result:
$ perf report -s cpu,comm --pid 0 --stdio
#
# Overhead CPU Command
# ........ ... .......
#
12.16% 000 swapper
3.09% 001 swapper
2.76% 002 swapper
2.23% 003 swapper
1.65% 007 swapper
1.65% 008 swapper
1.52% 009 swapper
1.51% 006 swapper
1.46% 004 swapper
1.34% 005 swapper
0.94% 010 swapper
0.90% 011 swapper
$ perf report -s cpu --pid 0 --stdio
#
# Overhead CPU
# ........ ...
#
12.16% 000
3.09% 001
2.76% 002
2.23% 003
1.65% 007
1.65% 008
1.52% 009
1.51% 006
1.46% 004
1.34% 005
0.94% 010
0.90% 011
$ perf report -s cpu --pid 0 --stdio --percentage relative
#
# Overhead CPU
# ........ ...
#
38.95% 000
9.92% 001
8.84% 002
7.16% 003
5.30% 007
5.28% 008
4.87% 009
4.83% 006
4.66% 004
4.30% 005
3.00% 010
2.89% 011
Note that the --hierarchy option provides groups rather than filtering
but shows similar result..
$ perf report -s pid,cpu --stdio --hierarchy
#
# Overhead Pid:Command / CPU
# ........... .......................
#
31.21% 0:swapper
12.16% 000
3.09% 001
2.76% 002
2.23% 003
1.65% 007
1.65% 008
1.52% 009
1.51% 006
1.46% 004
1.34% 005
0.94% 010
0.90% 011
19.15% 8618:getmail
...
-----------------------8<-------------------------------
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index 8d363d5e65a2..42b1bfd29ef8 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -262,6 +262,7 @@ enum auxtrace_error_type {
*/
struct events_stats {
u64 total_period;
+ u64 total_early_filtered_period;
u64 total_non_filtered_period;
u64 total_lost;
u64 total_lost_samples;
diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index 37a08f20730a..c7045411cce2 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -1017,12 +1017,21 @@ int hist_entry_iter__add(struct hist_entry_iter *iter, struct addr_location *al,
int max_stack_depth, void *arg)
{
int err, err2;
+ struct hists *hists = evsel__hists(iter->evsel);
err = sample__resolve_callchain(iter->sample, &callchain_cursor, &iter->parent,
iter->evsel, al, max_stack_depth);
if (err)
return err;
+ if (symbol__parent_filter(iter->parent))
+ al->filtered |= symbol__parent_filter(iter->parent);
+
+ if (al->filtered) {
+ hists->stats.total_early_filtered_period += iter->sample->period;
+ return 0;
+ }
+
iter->max_stack = max_stack_depth;
err = iter->ops->prepare_entry(iter, al);
@@ -1503,7 +1512,7 @@ static void hists__reset_filter_stats(struct hists *hists)
void hists__reset_stats(struct hists *hists)
{
hists->nr_entries = 0;
- hists->stats.total_period = 0;
+ hists->stats.total_period = hists->stats.total_early_filtered_period;
hists__reset_filter_stats(hists);
}
@@ -1530,7 +1539,7 @@ static void hierarchy_recalc_total_periods(struct hists *hists)
node = rb_first(&hists->entries);
- hists->stats.total_period = 0;
+ hists->stats.total_period = hists->stats.total_early_filtered_period;
hists->stats.total_non_filtered_period = 0;
/*
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