linux-kernel - Re: [PATCH 2/4] perf tool x86: Consolidate is

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Date:   Tue, 13 Jun 2023 12:49:50 -0700
From:   Ian Rogers <irogers@...gle.com>
To:     Ravi Bangoria <ravi.bangoria@....com>
Cc:     acme@...nel.org, jolsa@...nel.org, namhyung@...nel.org,
        mark.rutland@....com, peterz@...radead.org,
        adrian.hunter@...el.com, kan.liang@...ux.intel.com,
        james.clark@....com, alisaidi@...zon.com, leo.yan@...aro.org,
        maddy@...ux.ibm.com, linux-perf-users@...r.kernel.org,
        linux-kernel@...r.kernel.org, sandipan.das@....com,
        ananth.narayan@....com, santosh.shukla@....com
Subject: Re: [PATCH 2/4] perf tool x86: Consolidate is_amd check into single function

On Tue, Jun 13, 2023 at 2:56 AM Ravi Bangoria <ravi.bangoria@....com> wrote:
>
> There are multiple places where x86 specific code determines AMD vs
> Intel arch and acts based on that. Consolidate those checks into a
> single function.
>
> Signed-off-by: Ravi Bangoria <ravi.bangoria@....com>

Acked-by: Ian Rogers <irogers@...gle.com>

Thanks,
Ian

> ---
>  tools/perf/arch/x86/util/Build        |  1 +
>  tools/perf/arch/x86/util/env.c        | 19 +++++++++++++++++++
>  tools/perf/arch/x86/util/env.h        |  7 +++++++
>  tools/perf/arch/x86/util/evsel.c      | 16 ++--------------
>  tools/perf/arch/x86/util/mem-events.c | 19 ++-----------------
>  5 files changed, 31 insertions(+), 31 deletions(-)
>  create mode 100644 tools/perf/arch/x86/util/env.c
>  create mode 100644 tools/perf/arch/x86/util/env.h
>
> diff --git a/tools/perf/arch/x86/util/Build b/tools/perf/arch/x86/util/Build
> index 195ccfdef7aa..005907cb97d8 100644
> --- a/tools/perf/arch/x86/util/Build
> +++ b/tools/perf/arch/x86/util/Build
> @@ -10,6 +10,7 @@ perf-y += evlist.o
>  perf-y += mem-events.o
>  perf-y += evsel.o
>  perf-y += iostat.o
> +perf-y += env.o
>
>  perf-$(CONFIG_DWARF) += dwarf-regs.o
>  perf-$(CONFIG_BPF_PROLOGUE) += dwarf-regs.o
> diff --git a/tools/perf/arch/x86/util/env.c b/tools/perf/arch/x86/util/env.c
> new file mode 100644
> index 000000000000..33b87f8ac1cc
> --- /dev/null
> +++ b/tools/perf/arch/x86/util/env.c
> @@ -0,0 +1,19 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include "linux/string.h"
> +#include "util/env.h"
> +#include "env.h"
> +
> +bool x86__is_amd_cpu(void)
> +{
> +       struct perf_env env = { .total_mem = 0, };
> +       static int is_amd; /* 0: Uninitialized, 1: Yes, -1: No */
> +
> +       if (is_amd)
> +               goto ret;
> +
> +       perf_env__cpuid(&env);
> +       is_amd = env.cpuid && strstarts(env.cpuid, "AuthenticAMD") ? 1 : -1;
> +
> +ret:
> +       return is_amd >= 1 ? true : false;
> +}
> diff --git a/tools/perf/arch/x86/util/env.h b/tools/perf/arch/x86/util/env.h
> new file mode 100644
> index 000000000000..d78f080b6b3f
> --- /dev/null
> +++ b/tools/perf/arch/x86/util/env.h
> @@ -0,0 +1,7 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef _X86_ENV_H
> +#define _X86_ENV_H
> +
> +bool x86__is_amd_cpu(void);
> +
> +#endif /* _X86_ENV_H */
> diff --git a/tools/perf/arch/x86/util/evsel.c b/tools/perf/arch/x86/util/evsel.c
> index 25da46c8cca9..512c2d885d24 100644
> --- a/tools/perf/arch/x86/util/evsel.c
> +++ b/tools/perf/arch/x86/util/evsel.c
> @@ -8,6 +8,7 @@
>  #include "linux/string.h"
>  #include "evsel.h"
>  #include "util/debug.h"
> +#include "env.h"
>
>  #define IBS_FETCH_L3MISSONLY   (1ULL << 59)
>  #define IBS_OP_L3MISSONLY      (1ULL << 16)
> @@ -78,23 +79,10 @@ void arch__post_evsel_config(struct evsel *evsel, struct perf_event_attr *attr)
>  {
>         struct perf_pmu *evsel_pmu, *ibs_fetch_pmu, *ibs_op_pmu;
>         static int warned_once;
> -       /* 0: Uninitialized, 1: Yes, -1: No */
> -       static int is_amd;
>
> -       if (warned_once || is_amd == -1)
> +       if (warned_once || !x86__is_amd_cpu())
>                 return;
>
> -       if (!is_amd) {
> -               struct perf_env *env = evsel__env(evsel);
> -
> -               if (!perf_env__cpuid(env) || !env->cpuid ||
> -                   !strstarts(env->cpuid, "AuthenticAMD")) {
> -                       is_amd = -1;
> -                       return;
> -               }
> -               is_amd = 1;
> -       }
> -
>         evsel_pmu = evsel__find_pmu(evsel);
>         if (!evsel_pmu)
>                 return;
> diff --git a/tools/perf/arch/x86/util/mem-events.c b/tools/perf/arch/x86/util/mem-events.c
> index 32879d12a8d5..a8a782bcb121 100644
> --- a/tools/perf/arch/x86/util/mem-events.c
> +++ b/tools/perf/arch/x86/util/mem-events.c
> @@ -5,6 +5,7 @@
>  #include "map_symbol.h"
>  #include "mem-events.h"
>  #include "linux/string.h"
> +#include "env.h"
>
>  static char mem_loads_name[100];
>  static bool mem_loads_name__init;
> @@ -27,28 +28,12 @@ static struct perf_mem_event perf_mem_events_amd[PERF_MEM_EVENTS__MAX] = {
>         E("mem-ldst",   "ibs_op//",     "ibs_op"),
>  };
>
> -static int perf_mem_is_amd_cpu(void)
> -{
> -       struct perf_env env = { .total_mem = 0, };
> -
> -       perf_env__cpuid(&env);
> -       if (env.cpuid && strstarts(env.cpuid, "AuthenticAMD"))
> -               return 1;
> -       return -1;
> -}
> -
>  struct perf_mem_event *perf_mem_events__ptr(int i)
>  {
> -       /* 0: Uninitialized, 1: Yes, -1: No */
> -       static int is_amd;
> -
>         if (i >= PERF_MEM_EVENTS__MAX)
>                 return NULL;
>
> -       if (!is_amd)
> -               is_amd = perf_mem_is_amd_cpu();
> -
> -       if (is_amd == 1)
> +       if (x86__is_amd_cpu())
>                 return &perf_mem_events_amd[i];
>
>         return &perf_mem_events_intel[i];
> --
> 2.40.1
>