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Message-ID: <CAP-5=fVOp-FcRR5oLvMVvb0R3sMgd=qnORwZGwdK1BbcqOBhHA@mail.gmail.com>
Date: Mon, 14 Aug 2023 09:09:40 -0700
From: Ian Rogers <irogers@...gle.com>
To: John Garry <john.g.garry@...cle.com>
Cc: Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
Kan Liang <kan.liang@...ux.intel.com>,
Ravi Bangoria <ravi.bangoria@....com>,
Kajol Jain <kjain@...ux.ibm.com>,
linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/3] perf pmus: Add scan that ignores duplicates, use
for perf list
On Mon, Aug 14, 2023 at 8:57 AM Ian Rogers <irogers@...gle.com> wrote:
>
> On Fri, Aug 11, 2023 at 8:51 AM John Garry <john.g.garry@...cle.com> wrote:
> >
> > On 10/08/2023 22:49, Ian Rogers wrote:
> > > When there are multiple PMUs that differ only by suffix, by default
> > > just list the first one and skip all others. As the PMUs are sorted,
> > > the scan routine checks that the PMU names match and the numbers are
> > > consecutive. If "-v" is passed to "perf list" then list all PMUs.
> >
> > I really think that this should be merged with the next change. I don't
> > like the intermediate step of by default only printing the first PMU.
>
> Ack. I'll leave it as 3 patches and then leave it to Arnaldo squash as
> quite often he wants more patches.
>
> > >
> > > Signed-off-by: Ian Rogers <irogers@...gle.com>
> > > ---
> > > tools/perf/builtin-list.c | 8 +++++
> > > tools/perf/util/pmus.c | 54 ++++++++++++++++++++++++++++++++--
> > > tools/perf/util/print-events.h | 1 +
> > > 3 files changed, 61 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/tools/perf/builtin-list.c b/tools/perf/builtin-list.c
> > > index 7fec2cca759f..8fe4ddf02c14 100644
> > > --- a/tools/perf/builtin-list.c
> > > +++ b/tools/perf/builtin-list.c
> > > @@ -423,6 +423,13 @@ static void json_print_metric(void *ps __maybe_unused, const char *group,
> > > strbuf_release(&buf);
> > > }
> > >
> > > +static bool default_skip_duplicate_pmus(void *ps)
> > > +{
> > > + struct print_state *print_state = ps;
> > > +
> > > + return !print_state->long_desc;
> > > +}
> > > +
> > > int cmd_list(int argc, const char **argv)
> > > {
> > > int i, ret = 0;
> > > @@ -434,6 +441,7 @@ int cmd_list(int argc, const char **argv)
> > > .print_end = default_print_end,
> > > .print_event = default_print_event,
> > > .print_metric = default_print_metric,
> > > + .skip_duplicate_pmus = default_skip_duplicate_pmus,
> > > };
> > > const char *cputype = NULL;
> > > const char *unit_name = NULL;
> > > diff --git a/tools/perf/util/pmus.c b/tools/perf/util/pmus.c
> > > index 3581710667b0..5073843aca19 100644
> > > --- a/tools/perf/util/pmus.c
> > > +++ b/tools/perf/util/pmus.c
> > > @@ -275,6 +275,50 @@ struct perf_pmu *perf_pmus__scan_core(struct perf_pmu *pmu)
> > > return NULL;
> > > }
> > >
> > > +static struct perf_pmu *perf_pmus__scan_skip_duplicates(struct perf_pmu *pmu)
> > > +{
> > > + bool use_core_pmus = !pmu || pmu->is_core;
> > > + int last_pmu_name_len = 0;
> > > + unsigned long last_pmu_num = 0;
> > > + const char *last_pmu_name = (pmu && pmu->name) ? pmu->name : "";
> > > +
> > > + if (!pmu) {
> > > + pmu_read_sysfs(/*core_only=*/false);
> > > + pmu = list_prepare_entry(pmu, &core_pmus, list);
> > > + } else
> > > + last_pmu_name_len = pmu_name_len_no_suffix(pmu->name ?: "", &last_pmu_num);
> > > +
> > > + if (use_core_pmus) {
> > > + list_for_each_entry_continue(pmu, &core_pmus, list) {
> > > + unsigned long pmu_num = 0;
> > > + int pmu_name_len = pmu_name_len_no_suffix(pmu->name ?: "", &pmu_num);
> > > +
> > > + if (last_pmu_name_len == pmu_name_len &&
> > > + (last_pmu_num + 1 == pmu_num) &&
> > > + !strncmp(last_pmu_name, pmu->name ?: "", pmu_name_len)) {
> > > + last_pmu_num++;
> > > + continue;
> > > + }
> > > + return pmu;
> > > + }
> > > + pmu = NULL;
> >
> > you assign pmu NULL
> >
> > > + pmu = list_prepare_entry(pmu, &other_pmus, list);
> >
> > and then re-assign it. If list_prepare_entry() needs first arg = NULL,
> > then can just use NULL explicitly?
>
> Done.
So because of the macro magic in list_prepare_entry you can't
explicitly pass NULL here as doing so yields:
tools/include/linux/kernel.h:36:33: error: request for member ‘list’
in something not a structure or union
36 | const typeof(((type *)0)->member) * __mptr = (ptr); \
| ^~
Thanks,
Ian
> > > + }
> > > + list_for_each_entry_continue(pmu, &other_pmus, list) {
> > > + unsigned long pmu_num = 0;
> > > + int pmu_name_len = pmu_name_len_no_suffix(pmu->name ?: "", &pmu_num);
> > > +
> > > + if (last_pmu_name_len == pmu_name_len &&
> > > + (last_pmu_num + 1 == pmu_num) &&
> > > + !strncmp(last_pmu_name, pmu->name ?: "", pmu_name_len)) {
> > > + last_pmu_num++;
> > > + continue;
> >
> > Can some of this code be factored out from the previous patch? It's
> > doing something similar, right?
>
> The previous patch implemented list sorting and a list comparator
> whilst this patch is skipping PMUs if they follow the pattern:
> uncore_xyz_0
> uncore_xyz_1 <- skip
> uncore_xyz_2 <- skip
> The pmu_name_len_no_suffix is factored out and shared between both
> routines. The comparator doesn't maintain state whilst this code does.
> So I don't see a way to refactor things further.
>
> Thanks,
> Ian
>
> > > + }
> > > + return pmu;
> > > + }
> > > + return NULL;
> > > +}
> > > +
> > > const struct perf_pmu *perf_pmus__pmu_for_pmu_filter(const char *str)
> > > {
> > > struct perf_pmu *pmu = NULL;
> > > @@ -429,10 +473,16 @@ void perf_pmus__print_pmu_events(const struct print_callbacks *print_cb, void *p
> > > int printed = 0;
> > > int len, j;
> > > struct sevent *aliases;
> > > + struct perf_pmu *(*scan_fn)(struct perf_pmu *);
> > > +
> > > + if (print_cb->skip_duplicate_pmus(print_state))
> > > + scan_fn = perf_pmus__scan_skip_duplicates;
> > > + else
> > > + scan_fn = perf_pmus__scan;
> > >
> > > pmu = NULL;
> > > len = 0;
> > > - while ((pmu = perf_pmus__scan(pmu)) != NULL) {
> > > + while ((pmu = scan_fn(pmu)) != NULL) {
> > > list_for_each_entry(event, &pmu->aliases, list)
> > > len++;
> > > if (pmu->selectable)
> > > @@ -445,7 +495,7 @@ void perf_pmus__print_pmu_events(const struct print_callbacks *print_cb, void *p
> > > }
> > > pmu = NULL;
> > > j = 0;
> > > - while ((pmu = perf_pmus__scan(pmu)) != NULL) {
> > > + while ((pmu = scan_fn(pmu)) != NULL) {
> > > bool is_cpu = pmu->is_core;
> > >
> > > list_for_each_entry(event, &pmu->aliases, list) {
> > > diff --git a/tools/perf/util/print-events.h b/tools/perf/util/print-events.h
> > > index d7fab411e75c..bf4290bef0cd 100644
> > > --- a/tools/perf/util/print-events.h
> > > +++ b/tools/perf/util/print-events.h
> > > @@ -26,6 +26,7 @@ struct print_callbacks {
> > > const char *expr,
> > > const char *threshold,
> > > const char *unit);
> > > + bool (*skip_duplicate_pmus)(void *print_state);
> > > };
> > >
> > > /** Print all events, the default when no options are specified. */
> >
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