Re: [Patch v2 1/5] perf x86/topdown: Complete topdown slots/metrics events check

Liang, Kan
2024-07-08T13:28:31Z

On 2024-07-08 10:42 a.m., Dapeng Mi wrote:
> It's not complete to check whether an event is a topdown slots or
> topdown metrics event by only comparing the event name since user
> may assign the event by RAW format, e.g.
>
> perf stat -e '{instructions,cpu/r400/,cpu/r8300/}' sleep 1
>
> Performance counter stats for 'sleep 1':
>
> <not counted> instructions
> <not counted> cpu/r400/
> <not supported> cpu/r8300/
>
> 1.002917796 seconds time elapsed
>
> 0.002955000 seconds user
> 0.000000000 seconds sys
>
> The RAW format slots and topdown-be-bound events are not recognized and
> not regroup the events, and eventually cause error.
>
> Thus add two helpers arch_is_topdown_slots()/arch_is_topdown_metrics()
> to detect whether an event is topdown slots/metrics event by comparing
> the event config directly, and use these two helpers to replace the
> original event name comparisons.
>
> Signed-off-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
> ---
> tools/perf/arch/x86/util/evlist.c | 8 +++---
> tools/perf/arch/x86/util/evsel.c | 3 ++-
> tools/perf/arch/x86/util/topdown.c | 43 +++++++++++++++++++++++++++++-
> tools/perf/arch/x86/util/topdown.h | 2 ++
> 4 files changed, 50 insertions(+), 6 deletions(-)
>
> diff --git a/tools/perf/arch/x86/util/evlist.c b/tools/perf/arch/x86/util/evlist.c
> index b1ce0c52d88d..332e8907f43e 100644
> --- a/tools/perf/arch/x86/util/evlist.c
> +++ b/tools/perf/arch/x86/util/evlist.c
> @@ -78,14 +78,14 @@ int arch_evlist__cmp(const struct evsel *lhs, const struct evsel *rhs)
> if (topdown_sys_has_perf_metrics() &&
> (arch_evsel__must_be_in_group(lhs) || arch_evsel__must_be_in_group(rhs))) {
> /* Ensure the topdown slots comes first. */
> - if (strcasestr(lhs->name, "slots") && !strcasestr(lhs->name, "uops_retired.slots"))
> + if (arch_is_topdown_slots(lhs))
> return -1;
> - if (strcasestr(rhs->name, "slots") && !strcasestr(rhs->name, "uops_retired.slots"))
> + if (arch_is_topdown_slots(rhs))
> return 1;
> /* Followed by topdown events. */
> - if (strcasestr(lhs->name, "topdown") && !strcasestr(rhs->name, "topdown"))
> + if (arch_is_topdown_metrics(lhs) && !arch_is_topdown_metrics(rhs))
> return -1;
> - if (!strcasestr(lhs->name, "topdown") && strcasestr(rhs->name, "topdown"))
> + if (!arch_is_topdown_metrics(lhs) && arch_is_topdown_metrics(rhs))
> return 1;
> }
>
> diff --git a/tools/perf/arch/x86/util/evsel.c b/tools/perf/arch/x86/util/evsel.c
> index 090d0f371891..181f2ba0bb2a 100644
> --- a/tools/perf/arch/x86/util/evsel.c
> +++ b/tools/perf/arch/x86/util/evsel.c
> @@ -6,6 +6,7 @@
> #include "util/pmu.h"
> #include "util/pmus.h"
> #include "linux/string.h"
> +#include "topdown.h"
> #include "evsel.h"
> #include "util/debug.h"
> #include "env.h"
> @@ -44,7 +45,7 @@ bool arch_evsel__must_be_in_group(const struct evsel *evsel)
> strcasestr(evsel->name, "uops_retired.slots"))
> return false;
>
> - return strcasestr(evsel->name, "topdown") || strcasestr(evsel->name, "slots");
> + return arch_is_topdown_metrics(evsel) || arch_is_topdown_slots(evsel);
> }
>
> int arch_evsel__hw_name(struct evsel *evsel, char *bf, size_t size)
> diff --git a/tools/perf/arch/x86/util/topdown.c b/tools/perf/arch/x86/util/topdown.c
> index 3f9a267d4501..e805065bb7e1 100644
> --- a/tools/perf/arch/x86/util/topdown.c
> +++ b/tools/perf/arch/x86/util/topdown.c
> @@ -32,6 +32,47 @@ bool topdown_sys_has_perf_metrics(void)
> }
>
> #define TOPDOWN_SLOTS 0x0400
> +bool arch_is_topdown_slots(const struct evsel *evsel)
> +{
> + if (evsel->core.attr.config == TOPDOWN_SLOTS)
> + return true;
> +
> + return false;
> +}
> +
> +static int compare_topdown_event(void *vstate, struct pmu_event_info *info)
> +{
> + int *config = vstate;
> + int event = 0;
> + int umask = 0;
> + char *str;
> +

The compare is only needed for the "topdown" event.
Check the name first before the sscanf and compare.

if (!strcasestr(info->name, "topdown"))
return 0;

> + str = strcasestr(info->str, "event=");
> + if (str)
> + sscanf(str, "event=%x", &event);
> +
> + str = strcasestr(info->str, "umask=");
> + if (str)
> + sscanf(str, "umask=%x", &umask);
> +
> + if (strcasestr(info->name, "topdown") && event == 0 &&
> + *config == (event | umask << 8))
> + return 1;
> +
> + return 0;
> +}
> +
> +bool arch_is_topdown_metrics(const struct evsel *evsel)
> +{
> + struct perf_pmu *pmu = evsel__find_pmu(evsel);
> + int config = evsel->core.attr.config;
> +

The topdown events are only available for the core PMU.
You may want to return earlier for the !core PMUs.

if (!pmu || !pmu->is_core)
return false;

Thanks,
Kan
> + if (pmu && perf_pmu__for_each_event(pmu, false, &config,
> + compare_topdown_event))
> + return true;
> +
> + return false;
> +}
>
> /*
> * Check whether a topdown group supports sample-read.
> @@ -44,7 +85,7 @@ bool arch_topdown_sample_read(struct evsel *leader)
> if (!evsel__sys_has_perf_metrics(leader))
> return false;
>
> - if (leader->core.attr.config == TOPDOWN_SLOTS)
> + if (arch_is_topdown_slots(leader))
> return true;
>
> return false;
> diff --git a/tools/perf/arch/x86/util/topdown.h b/tools/perf/arch/x86/util/topdown.h
> index 46bf9273e572..1bae9b1822d7 100644
> --- a/tools/perf/arch/x86/util/topdown.h
> +++ b/tools/perf/arch/x86/util/topdown.h
> @@ -3,5 +3,7 @@
> #define _TOPDOWN_H 1
>
> bool topdown_sys_has_perf_metrics(void);
> +bool arch_is_topdown_slots(const struct evsel *evsel);
> +bool arch_is_topdown_metrics(const struct evsel *evsel);
>
> #endif