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    SubjectRe: [PATCH 2/9] perf tools: Support the auxiliary event
    Em Tue, Feb 02, 2021 at 12:09:06PM -0800, kan.liang@linux.intel.com escreveu:
    > From: Kan Liang <kan.liang@linux.intel.com>
    > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
    > index c26ea822..c48f6de 100644
    > --- a/tools/perf/util/evsel.c
    > +++ b/tools/perf/util/evsel.c
    > @@ -2689,6 +2689,9 @@ int evsel__open_strerror(struct evsel *evsel, struct target *target,
    > if (perf_missing_features.aux_output)
    > return scnprintf(msg, size, "The 'aux_output' feature is not supported, update the kernel.");
    > break;
    > + case ENODATA:
    > + return scnprintf(msg, size, "Cannot collect data source with the load latency event alone. "
    > + "Please add an auxiliary event in front of the load latency event.");

    Are you sure this is the only case where ENODATA comes out from
    perf_event_open()? Well, according to your comment in:

    61b985e3e775a3a7 ("perf/x86/intel: Add perf core PMU support for Sapphire Rapids")

    It should be at that point in time, so its safe to merge as-is, but then
    I think this is fragile, what if someone else, in the future, not
    knowing that ENODATA is supposed to be used only with that ancient CPU,
    Sapphire Rapids, uses it? :-)

    Please consider adding a check before assuming ENODATA is for this
    specific case.

    Back to processing the other patches.

    - Arnaldo

    > default:
    > break;
    > }
    > diff --git a/tools/perf/util/mem-events.c b/tools/perf/util/mem-events.c
    > index 19007e4..3edfb88 100644
    > --- a/tools/perf/util/mem-events.c
    > +++ b/tools/perf/util/mem-events.c
    > @@ -56,6 +56,11 @@ char * __weak perf_mem_events__name(int i)
    > return (char *)e->name;
    > }
    >
    > +__weak bool is_mem_loads_aux_event(struct evsel *leader __maybe_unused)
    > +{
    > + return false;
    > +}
    > +
    > int perf_mem_events__parse(const char *str)
    > {
    > char *tok, *saveptr = NULL;
    > diff --git a/tools/perf/util/mem-events.h b/tools/perf/util/mem-events.h
    > index 5ef1782..045a507 100644
    > --- a/tools/perf/util/mem-events.h
    > +++ b/tools/perf/util/mem-events.h
    > @@ -9,6 +9,7 @@
    > #include <linux/refcount.h>
    > #include <linux/perf_event.h>
    > #include "stat.h"
    > +#include "evsel.h"
    >
    > struct perf_mem_event {
    > bool record;
    > @@ -39,6 +40,7 @@ int perf_mem_events__init(void);
    >
    > char *perf_mem_events__name(int i);
    > struct perf_mem_event *perf_mem_events__ptr(int i);
    > +bool is_mem_loads_aux_event(struct evsel *leader);
    >
    > void perf_mem_events__list(void);
    >
    > diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
    > index 9db5097..0b36285 100644
    > --- a/tools/perf/util/parse-events.l
    > +++ b/tools/perf/util/parse-events.l
    > @@ -356,6 +356,7 @@ bpf-output { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_BPF_OUT
    > cycles-ct |
    > cycles-t |
    > mem-loads |
    > +mem-loads-aux |
    > mem-stores |
    > topdown-[a-z-]+ |
    > tx-capacity-[a-z-]+ |
    > diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c
    > index e70c9dd..d0735fb 100644
    > --- a/tools/perf/util/record.c
    > +++ b/tools/perf/util/record.c
    > @@ -15,6 +15,8 @@
    > #include "record.h"
    > #include "../perf-sys.h"
    > #include "topdown.h"
    > +#include "map_symbol.h"
    > +#include "mem-events.h"
    >
    > /*
    > * evsel__config_leader_sampling() uses special rules for leader sampling.
    > @@ -25,7 +27,8 @@ static struct evsel *evsel__read_sampler(struct evsel *evsel, struct evlist *evl
    > {
    > struct evsel *leader = evsel->leader;
    >
    > - if (evsel__is_aux_event(leader) || arch_topdown_sample_read(leader)) {
    > + if (evsel__is_aux_event(leader) || arch_topdown_sample_read(leader) ||
    > + is_mem_loads_aux_event(leader)) {
    > evlist__for_each_entry(evlist, evsel) {
    > if (evsel->leader == leader && evsel != evsel->leader)
    > return evsel;
    > --
    > 2.7.4
    >

    --

    - Arnaldo

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