linux-kernel - Re: [PATCH V2 5/5] perf mem: Clean up is_mem_loads_aux

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Message-ID: <20231209062709.GD2116834@leoy-yangtze.lan>
Date:   Sat, 9 Dec 2023 14:27:09 +0800
From:   Leo Yan <leo.yan@...aro.org>
To:     kan.liang@...ux.intel.com
Cc:     acme@...nel.org, irogers@...gle.com, peterz@...radead.org,
        mingo@...hat.com, namhyung@...nel.org, jolsa@...nel.org,
        adrian.hunter@...el.com, john.g.garry@...cle.com, will@...nel.org,
        james.clark@....com, mike.leach@...aro.org,
        yuhaixin.yhx@...ux.alibaba.com, renyu.zj@...ux.alibaba.com,
        tmricht@...ux.ibm.com, ravi.bangoria@....com,
        linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH V2 5/5] perf mem: Clean up is_mem_loads_aux_event()

On Thu, Dec 07, 2023 at 11:23:38AM -0800, kan.liang@...ux.intel.com wrote:
> From: Kan Liang <kan.liang@...ux.intel.com>
> 
> The aux_event can be retrieved from the perf_pmu now. Implement a
> generic support.
> 
> Reviewed-by: Ian Rogers <irogers@...gle.com>
> Tested-by: Ravi Bangoria <ravi.bangoria@....com>
> Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
> ---
>  tools/perf/arch/x86/util/mem-events.c | 23 ++++-------------------
>  tools/perf/util/mem-events.c          | 14 ++++++++++++--
>  2 files changed, 16 insertions(+), 21 deletions(-)
> 
> diff --git a/tools/perf/arch/x86/util/mem-events.c b/tools/perf/arch/x86/util/mem-events.c
> index b776d849fc64..62df03e91c7e 100644
> --- a/tools/perf/arch/x86/util/mem-events.c
> +++ b/tools/perf/arch/x86/util/mem-events.c
> @@ -1,11 +1,9 @@
>  // SPDX-License-Identifier: GPL-2.0
> -#include "util/pmu.h"
> -#include "util/pmus.h"
> -#include "util/env.h"
> -#include "map_symbol.h"
> -#include "mem-events.h"
>  #include "linux/string.h"
> -#include "env.h"
> +#include "util/map_symbol.h"
> +#include "util/mem-events.h"
> +#include "mem-events.h"
> +
>  
>  #define MEM_LOADS_AUX		0x8203
>  
> @@ -28,16 +26,3 @@ struct perf_mem_event perf_mem_events_amd[PERF_MEM_EVENTS__MAX] = {
>  	E(NULL,		NULL,		NULL,	false,	0),
>  	E("mem-ldst",	"%s//",		NULL,	false,	0),
>  };
> -
> -bool is_mem_loads_aux_event(struct evsel *leader)
> -{
> -	struct perf_pmu *pmu = perf_pmus__find("cpu");
> -
> -	if (!pmu)
> -		pmu = perf_pmus__find("cpu_core");
> -
> -	if (pmu && !perf_pmu__have_event(pmu, "mem-loads-aux"))
> -		return false;
> -
> -	return leader->core.attr.config == MEM_LOADS_AUX;
> -}
> diff --git a/tools/perf/util/mem-events.c b/tools/perf/util/mem-events.c
> index 0d174f161034..d418320e52e3 100644
> --- a/tools/perf/util/mem-events.c
> +++ b/tools/perf/util/mem-events.c
> @@ -103,9 +103,19 @@ static const char *perf_pmu__mem_events_name(int i, struct perf_pmu *pmu)
>  	return NULL;
>  }
>  
> -__weak bool is_mem_loads_aux_event(struct evsel *leader __maybe_unused)
> +bool is_mem_loads_aux_event(struct evsel *leader)
>  {
> -	return false;
> +	struct perf_pmu *pmu = leader->pmu;
> +	struct perf_mem_event *e;
> +
> +	if (!pmu || !pmu->mem_events)
> +		return false;
> +
> +	e = &pmu->mem_events[PERF_MEM_EVENTS__LOAD];
> +	if (!e->aux_event)
> +		return false;
> +
> +	return leader->core.attr.config == e->aux_event;
>  }

I am wandering if we need to set the field 'aux_event' for Arm SPE.

So a quesiton maybe is not relevant with this patch actually, we can
see is_mem_loads_aux_event() is invoked in the file util/record.c:

  static struct evsel *evsel__read_sampler(struct evsel *evsel, struct evlist *evlist)
  {
          struct evsel *leader = evsel__leader(evsel);

          if (evsel__is_aux_event(leader) || arch_topdown_sample_read(leader) ||
              is_mem_loads_aux_event(leader)) {
              ...
          }
  
          return leader;
  }

Has evsel__is_aux_event() covered the memory load aux event?  If it's,
then is_mem_loads_aux_event() is not needed anymore.

Thanks,
Leo