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Message-ID: <CAP-5=fVqhvR-3ya6GLs98A_1hTYX=jjjBkCbxMYb+2ZT5FRk1w@mail.gmail.com>
Date: Thu, 18 Jul 2024 08:07:06 -0700
From: Ian Rogers <irogers@...gle.com>
To: James Clark <james.clark@...aro.org>
Cc: Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>, Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>, Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>, Kan Liang <kan.liang@...ux.intel.com>,
Bjorn Helgaas <bhelgaas@...gle.com>, Jonathan Corbet <corbet@....net>, James Clark <james.clark@....com>,
Ravi Bangoria <ravi.bangoria@....com>, Dominique Martinet <asmadeus@...ewreck.org>,
linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
ananth.narayan@....com, gautham.shenoy@....com, kprateek.nayak@....com,
sandipan.das@....com
Subject: Re: [PATCH v2 6/6] perf parse-events: Add "cpu" term to set the CPU
an event is recorded on
On Thu, Jul 18, 2024 at 7:10 AM James Clark <james.clark@...aro.org> wrote:
>
>
>
> On 18/07/2024 1:30 am, Ian Rogers wrote:
> > The -C option allows the CPUs for a list of events to be specified but
> > its not possible to set the CPU for a single event. Add a term to
> > allow this. The term isn't a general CPU list due to ',' already being
> > a special character in event parsing instead multiple cpu= terms may
> > be provided and they will be merged/unioned together.
> >
> > An example of mixing different types of events counted on different CPUs:
> > ```
> > $ perf stat -A -C 0,4-5,8 -e "instructions/cpu=0/,l1d-misses/cpu=4,cpu=5/,inst_retired.any/cpu=8/,cycles" -a sleep 0.1
> >
>
> I ran into cpu=N having no effect unless -C is also used. For example:
>
> $ perf stat -vv -e branch-misses/cpu=1/ -- true
>
> sys_perf_event_open: pid 10233 cpu -1 group_fd -1 flags 0x8 = 3
>
> Vs:
>
> $ perf stat -C 0,1 -vv -e branch-misses/cpu=1/ -- true
>
> sys_perf_event_open: pid -1 cpu 1 group_fd -1 flags 0x8 = 3
>
> Is it possible to have a warning or error in that case? Seems like it's
> quite likely to confuse a user.
Agreed. We have similar warnings for "-A". Tbh, there's no reason we
can support this, perf_event_open does. The evlist propagate maps
logic in my mind is crazy. I agree with a need to summarize the cpu
maps in the evlist, but the code changes evsel cpu maps in ways that
are brittle - for example, in this series I try to fix that legacy
hardware and hardware cache events aren't considered core. Rather than
processing command line options, the propagate maps fudge, I just wish
event parsing would do parsing and the events be pretty immutable
after that. The problem comes if you do -e then -C or -C then -e, as
our command line processing is ordering dependent.
Thanks,
Ian
> Other than that it seems to work ok.
>
> WRT the RAPL issue [1], I didn't quite follow how these two things will
> join up. Doesn't this only end up setting the cpu argument to
> perf_event_open(), which already aggregates per package rather than per
> core, even if the cpu is set? And the fix for that behavior was rejected
> because it would break Intel metrics [2].
>
> Maybe I'm missing a piece.
>
> [1]:
> https://lore.kernel.org/lkml/CAP-5=fXXuWchzUK0n5KTH8kamr=DQoEni+bUoo8f-4j8Y+eMBg@mail.gmail.com/
> [2]:
> https://lore.kernel.org/lkml/3e766f0e-37d4-0f82-3868-31b14228868d@linux.intel.com/
>
> James
>
> > Performance counter stats for 'system wide':
> >
> > CPU0 368,647 instructions/cpu=0/ # 0.26 insn per cycle
> > CPU4 <not counted> instructions/cpu=0/
> > CPU5 <not counted> instructions/cpu=0/
> > CPU8 <not counted> instructions/cpu=0/
> > CPU0 <not counted> l1d-misses [cpu]
> > CPU4 203,377 l1d-misses [cpu]
> > CPU5 138,231 l1d-misses [cpu]
> > CPU8 <not counted> l1d-misses [cpu]
> > CPU0 <not counted> cpu/cpu=8/
> > CPU4 <not counted> cpu/cpu=8/
> > CPU5 <not counted> cpu/cpu=8/
> > CPU8 943,861 cpu/cpu=8/
> > CPU0 1,412,071 cycles
> > CPU4 20,362,900 cycles
> > CPU5 10,172,725 cycles
> > CPU8 2,406,081 cycles
> >
> > 0.102925309 seconds time elapsed
> > ```
> >
> > Note, the event name of inst_retired.any is missing, reported as
> > cpu/cpu=8/, as there are unmerged uniquify fixes:
> > https://lore.kernel.org/lkml/20240510053705.2462258-3-irogers@google.com/
> >
> > An example of spreading uncore overhead across two CPUs:
> > ```
> > $ perf stat -A -e "data_read/cpu=0/,data_write/cpu=1/" -a sleep 0.1
> >
> > Performance counter stats for 'system wide':
> >
> > CPU0 223.65 MiB uncore_imc_free_running_0/cpu=0/
> > CPU0 223.66 MiB uncore_imc_free_running_1/cpu=0/
> > CPU0 <not counted> MiB uncore_imc_free_running_0/cpu=1/
> > CPU1 5.78 MiB uncore_imc_free_running_0/cpu=1/
> > CPU0 <not counted> MiB uncore_imc_free_running_1/cpu=1/
> > CPU1 5.74 MiB uncore_imc_free_running_1/cpu=1/
> > ```
> >
> > Manually fixing the output it should be:
> > ```
> > CPU0 223.65 MiB uncore_imc_free_running_0/data_read,cpu=0/
> > CPU0 223.66 MiB uncore_imc_free_running_1/data_read,cpu=0/
> > CPU1 5.78 MiB uncore_imc_free_running_0/data_write,cpu=1/
> > CPU1 5.74 MiB uncore_imc_free_running_1/data_write,cpu=1/
> > ```
> >
> > That is data_read from 2 PMUs was counted on CPU0 and data_write was
> > counted on CPU1.
> >
> > Signed-off-by: Ian Rogers <irogers@...gle.com>
> > ---
> > tools/perf/Documentation/perf-list.txt | 9 ++++
> > tools/perf/util/evsel_config.h | 1 +
> > tools/perf/util/parse-events.c | 73 ++++++++++++++++++++++----
> > tools/perf/util/parse-events.h | 3 +-
> > tools/perf/util/parse-events.l | 1 +
> > tools/perf/util/pmu.c | 1 +
> > 6 files changed, 77 insertions(+), 11 deletions(-)
> >
> > diff --git a/tools/perf/Documentation/perf-list.txt b/tools/perf/Documentation/perf-list.txt
> > index 6bf2468f59d3..15511afe94a1 100644
> > --- a/tools/perf/Documentation/perf-list.txt
> > +++ b/tools/perf/Documentation/perf-list.txt
> > @@ -273,6 +273,15 @@ Sums up the event counts for all hardware threads in a core, e.g.:
> >
> > perf stat -e cpu/event=0,umask=0x3,percore=1/
> >
> > +cpu:
> > +
> > +Specifies the CPU to open the event upon. The value may be repeated to
> > +specify opening the event on multiple CPUs:
> > +
> > +
> > + perf stat -e instructions/cpu=0,cpu=2/,cycles/cpu=1,cpu=2/ -a sleep 1
> > + perf stat -e data_read/cpu=0/,data_write/cpu=1/ -a sleep 1
> > +
> >
> > EVENT GROUPS
> > ------------
> > diff --git a/tools/perf/util/evsel_config.h b/tools/perf/util/evsel_config.h
> > index aee6f808b512..9630c4a24721 100644
> > --- a/tools/perf/util/evsel_config.h
> > +++ b/tools/perf/util/evsel_config.h
> > @@ -47,6 +47,7 @@ struct evsel_config_term {
> > u32 aux_sample_size;
> > u64 cfg_chg;
> > char *str;
> > + int cpu;
> > } val;
> > bool weak;
> > };
> > diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> > index 8c0c33361c5e..85faef85b8de 100644
> > --- a/tools/perf/util/parse-events.c
> > +++ b/tools/perf/util/parse-events.c
> > @@ -7,6 +7,7 @@
> > #include <errno.h>
> > #include <sys/ioctl.h>
> > #include <sys/param.h>
> > +#include "cpumap.h"
> > #include "term.h"
> > #include "evlist.h"
> > #include "evsel.h"
> > @@ -177,6 +178,26 @@ static char *get_config_name(const struct parse_events_terms *head_terms)
> > return get_config_str(head_terms, PARSE_EVENTS__TERM_TYPE_NAME);
> > }
> >
> > +static struct perf_cpu_map *get_config_cpu(const struct parse_events_terms *head_terms)
> > +{
> > + struct parse_events_term *term;
> > + struct perf_cpu_map *cpus = NULL;
> > +
> > + if (!head_terms)
> > + return NULL;
> > +
> > + list_for_each_entry(term, &head_terms->terms, list) {
> > + if (term->type_term == PARSE_EVENTS__TERM_TYPE_CPU) {
> > + struct perf_cpu_map *cpu = perf_cpu_map__new_int(term->val.num);
> > +
> > + cpus = perf_cpu_map__merge(cpus, cpu);
> > + perf_cpu_map__put(cpu);
> > + }
> > + }
> > +
> > + return cpus;
> > +}
> > +
> > /**
> > * fix_raw - For each raw term see if there is an event (aka alias) in pmu that
> > * matches the raw's string value. If the string value matches an
> > @@ -468,11 +489,12 @@ int parse_events_add_cache(struct list_head *list, int *idx, const char *name,
> > bool found_supported = false;
> > const char *config_name = get_config_name(parsed_terms);
> > const char *metric_id = get_config_metric_id(parsed_terms);
> > + struct perf_cpu_map *cpus = get_config_cpu(parsed_terms);
> > + int ret = 0;
> >
> > while ((pmu = perf_pmus__scan(pmu)) != NULL) {
> > LIST_HEAD(config_terms);
> > struct perf_event_attr attr;
> > - int ret;
> >
> > if (parse_events__filter_pmu(parse_state, pmu))
> > continue;
> > @@ -486,7 +508,7 @@ int parse_events_add_cache(struct list_head *list, int *idx, const char *name,
> > parsed_terms,
> > perf_pmu__auto_merge_stats(pmu));
> > if (ret)
> > - return ret;
> > + goto out_err;
> > continue;
> > }
> >
> > @@ -506,20 +528,27 @@ int parse_events_add_cache(struct list_head *list, int *idx, const char *name,
> >
> > if (parsed_terms) {
> > if (config_attr(&attr, parsed_terms, parse_state->error,
> > - config_term_common))
> > - return -EINVAL;
> > -
> > - if (get_config_terms(parsed_terms, &config_terms))
> > - return -ENOMEM;
> > + config_term_common)) {
> > + ret = -EINVAL;
> > + goto out_err;
> > + }
> > + if (get_config_terms(parsed_terms, &config_terms)) {
> > + ret = -ENOMEM;
> > + goto out_err;
> > + }
> > }
> >
> > if (__add_event(list, idx, &attr, /*init_attr*/true, config_name ?: name,
> > metric_id, pmu, &config_terms, /*auto_merge_stats=*/false,
> > - /*cpu_list=*/NULL) == NULL)
> > - return -ENOMEM;
> > + cpus) == NULL)
> > + ret = -ENOMEM;
> >
> > free_config_terms(&config_terms);
> > + if (ret)
> > + goto out_err;
> > }
> > +out_err:
> > + perf_cpu_map__put(cpus);
> > return found_supported ? 0 : -EINVAL;
> > }
> >
> > @@ -814,6 +843,7 @@ static const char *config_term_name(enum parse_events__term_type term_type)
> > [PARSE_EVENTS__TERM_TYPE_RAW] = "raw",
> > [PARSE_EVENTS__TERM_TYPE_LEGACY_CACHE] = "legacy-cache",
> > [PARSE_EVENTS__TERM_TYPE_HARDWARE] = "hardware",
> > + [PARSE_EVENTS__TERM_TYPE_CPU] = "cpu",
> > };
> > if ((unsigned int)term_type >= __PARSE_EVENTS__TERM_TYPE_NR)
> > return "unknown term";
> > @@ -843,6 +873,7 @@ config_term_avail(enum parse_events__term_type term_type, struct parse_events_er
> > case PARSE_EVENTS__TERM_TYPE_METRIC_ID:
> > case PARSE_EVENTS__TERM_TYPE_SAMPLE_PERIOD:
> > case PARSE_EVENTS__TERM_TYPE_PERCORE:
> > + case PARSE_EVENTS__TERM_TYPE_CPU:
> > return true;
> > case PARSE_EVENTS__TERM_TYPE_USER:
> > case PARSE_EVENTS__TERM_TYPE_SAMPLE_FREQ:
> > @@ -986,6 +1017,15 @@ do { \
> > return -EINVAL;
> > }
> > break;
> > + case PARSE_EVENTS__TERM_TYPE_CPU:
> > + CHECK_TYPE_VAL(NUM);
> > + if (term->val.num >= (u64)cpu__max_present_cpu().cpu) {
> > + parse_events_error__handle(err, term->err_val,
> > + strdup("too big"),
> > + NULL);
> > + return -EINVAL;
> > + }
> > + break;
> > case PARSE_EVENTS__TERM_TYPE_DRV_CFG:
> > case PARSE_EVENTS__TERM_TYPE_USER:
> > case PARSE_EVENTS__TERM_TYPE_LEGACY_CACHE:
> > @@ -1112,6 +1152,7 @@ static int config_term_tracepoint(struct perf_event_attr *attr,
> > case PARSE_EVENTS__TERM_TYPE_RAW:
> > case PARSE_EVENTS__TERM_TYPE_LEGACY_CACHE:
> > case PARSE_EVENTS__TERM_TYPE_HARDWARE:
> > + case PARSE_EVENTS__TERM_TYPE_CPU:
> > default:
> > if (err) {
> > parse_events_error__handle(err, term->err_term,
> > @@ -1243,6 +1284,7 @@ do { \
> > case PARSE_EVENTS__TERM_TYPE_RAW:
> > case PARSE_EVENTS__TERM_TYPE_LEGACY_CACHE:
> > case PARSE_EVENTS__TERM_TYPE_HARDWARE:
> > + case PARSE_EVENTS__TERM_TYPE_CPU:
> > default:
> > break;
> > }
> > @@ -1296,6 +1338,7 @@ static int get_config_chgs(struct perf_pmu *pmu, struct parse_events_terms *head
> > case PARSE_EVENTS__TERM_TYPE_RAW:
> > case PARSE_EVENTS__TERM_TYPE_LEGACY_CACHE:
> > case PARSE_EVENTS__TERM_TYPE_HARDWARE:
> > + case PARSE_EVENTS__TERM_TYPE_CPU:
> > default:
> > break;
> > }
> > @@ -1350,6 +1393,7 @@ static int __parse_events_add_numeric(struct parse_events_state *parse_state,
> > struct perf_event_attr attr;
> > LIST_HEAD(config_terms);
> > const char *name, *metric_id;
> > + struct perf_cpu_map *cpus;
> > int ret;
> >
> > memset(&attr, 0, sizeof(attr));
> > @@ -1371,9 +1415,11 @@ static int __parse_events_add_numeric(struct parse_events_state *parse_state,
> >
> > name = get_config_name(head_config);
> > metric_id = get_config_metric_id(head_config);
> > + cpus = get_config_cpu(head_config);
> > ret = __add_event(list, &parse_state->idx, &attr, /*init_attr*/true, name,
> > metric_id, pmu, &config_terms, /*auto_merge_stats=*/false,
> > - /*cpu_list=*/NULL) ? 0 : -ENOMEM;
> > + cpus) ? 0 : -ENOMEM;
> > + perf_cpu_map__put(cpus);
> > free_config_terms(&config_terms);
> > return ret;
> > }
> > @@ -1440,6 +1486,7 @@ static int parse_events_add_pmu(struct parse_events_state *parse_state,
> > LIST_HEAD(config_terms);
> > struct parse_events_terms parsed_terms;
> > bool alias_rewrote_terms = false;
> > + struct perf_cpu_map *term_cpu = NULL;
> > int ret = 0;
> >
> > if (verbose > 1) {
> > @@ -1531,6 +1578,12 @@ static int parse_events_add_pmu(struct parse_events_state *parse_state,
> > goto out_err;
> > }
> >
> > + term_cpu = get_config_cpu(&parsed_terms);
> > + if (!perf_cpu_map__is_empty(term_cpu)) {
> > + perf_cpu_map__put(info.cpus);
> > + info.cpus = term_cpu;
> > + term_cpu = NULL;
> > + }
> > evsel = __add_event(list, &parse_state->idx, &attr, /*init_attr=*/true,
> > get_config_name(&parsed_terms),
> > get_config_metric_id(&parsed_terms), pmu,
> > diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
> > index e13de2c8b706..b03857499030 100644
> > --- a/tools/perf/util/parse-events.h
> > +++ b/tools/perf/util/parse-events.h
> > @@ -79,7 +79,8 @@ enum parse_events__term_type {
> > PARSE_EVENTS__TERM_TYPE_RAW,
> > PARSE_EVENTS__TERM_TYPE_LEGACY_CACHE,
> > PARSE_EVENTS__TERM_TYPE_HARDWARE,
> > -#define __PARSE_EVENTS__TERM_TYPE_NR (PARSE_EVENTS__TERM_TYPE_HARDWARE + 1)
> > + PARSE_EVENTS__TERM_TYPE_CPU,
> > +#define __PARSE_EVENTS__TERM_TYPE_NR (PARSE_EVENTS__TERM_TYPE_CPU + 1)
> > };
> >
> > struct parse_events_term {
> > diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
> > index 16045c383ada..e06097a62796 100644
> > --- a/tools/perf/util/parse-events.l
> > +++ b/tools/perf/util/parse-events.l
> > @@ -330,6 +330,7 @@ percore { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_PERCORE); }
> > aux-output { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_AUX_OUTPUT); }
> > aux-sample-size { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_AUX_SAMPLE_SIZE); }
> > metric-id { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_METRIC_ID); }
> > +cpu { return term(yyscanner, PARSE_EVENTS__TERM_TYPE_CPU); }
> > cpu-cycles|cycles { return hw_term(yyscanner, PERF_COUNT_HW_CPU_CYCLES); }
> > stalled-cycles-frontend|idle-cycles-frontend { return hw_term(yyscanner, PERF_COUNT_HW_STALLED_CYCLES_FRONTEND); }
> > stalled-cycles-backend|idle-cycles-backend { return hw_term(yyscanner, PERF_COUNT_HW_STALLED_CYCLES_BACKEND); }
> > diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> > index 280b2499c861..27e2ff23799e 100644
> > --- a/tools/perf/util/pmu.c
> > +++ b/tools/perf/util/pmu.c
> > @@ -1767,6 +1767,7 @@ int perf_pmu__for_each_format(struct perf_pmu *pmu, void *state, pmu_format_call
> > "percore",
> > "aux-output",
> > "aux-sample-size=number",
> > + "cpu=number",
> > };
> > struct perf_pmu_format *format;
> > int ret;
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