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

[Liang, Kan]

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@xxxxxxxxxxxxxxx>
> ---
>  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