Re: [PATCH] perf stat: Add Topdown metrics L2 events as default events

[Namhyung Kim]

Hi Kan,

On Thu, Jul 8, 2021 at 9:04 AM <kan.liang@xxxxxxxxx> wrote:
>
> From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
>
> The Topdown Microarchitecture Analysis (TMA) Method is a structured
> analysis methodology to identify critical performance bottlenecks in
> out-of-order processors. The Topdown metrics L1 event was added as
> default events in the commit 42641d6f4d15 ("perf stat: Add Topdown
> metrics events as default events"). From the Sapphire Rapids server and
> later platforms, the same dedicated "metrics" register is extended to
> support both L1 and L2 events. Add both L1 and L2 Topdown metrics events
> as default events to enrich the default measuring information, if the
> new measurement register is available. On legacy systems there is no
> change to avoid extra multiplexing.
>
> The topdown_level indicates the max metrics level for the top-down
> statistics. Set it to 2 to display all L1 and L2 Topdown metrics events.
>
> With the patch:
>
>  $ perf stat sleep 1
>
>  Performance counter stats for 'sleep 1':
>
>               0.59 msec task-clock                #    0.001 CPUs utilized
>                  1      context-switches          #    1.687 K/sec
>                  0      cpu-migrations            #    0.000 /sec
>                 76      page-faults               #  128.198 K/sec
>          1,405,318      cycles                    #    2.371 GHz
>          1,471,136      instructions              #    1.05  insn per cycle
>            310,132      branches                  #  523.136 M/sec
>             10,435      branch-misses             #    3.36% of all branches
>          8,431,908      slots                     #   14.223 G/sec
>          1,554,116      topdown-retiring          #     18.4% retiring
>          1,289,585      topdown-bad-spec          #     15.2% bad speculation
>          2,810,636      topdown-fe-bound          #     33.2% frontend bound
>          2,810,636      topdown-be-bound          #     33.2% backend bound
>            231,464      topdown-heavy-ops         #      2.7% heavy operations       #     15.6% light operations
>          1,223,453      topdown-br-mispredict     #     14.5% branch mispredict      #      0.8% machine clears
>          1,884,779      topdown-fetch-lat         #     22.3% fetch latency          #     10.9% fetch bandwidth
>          1,454,917      topdown-mem-bound         #     17.2% memory bound           #     16.0% Core bound
>
>        1.001179699 seconds time elapsed
>
>        0.000000000 seconds user
>        0.001238000 seconds sys
>
> Reviewed-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>

Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>

Thanks,
Namhyung


> ---
>  tools/perf/arch/x86/util/evlist.c | 6 +++++-
>  tools/perf/builtin-stat.c         | 3 +++
>  2 files changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/arch/x86/util/evlist.c b/tools/perf/arch/x86/util/evlist.c
> index 8c6732c..0b09510 100644
> --- a/tools/perf/arch/x86/util/evlist.c
> +++ b/tools/perf/arch/x86/util/evlist.c
> @@ -5,11 +5,15 @@
>  #include "util/parse-events.h"
>
>  #define TOPDOWN_L1_EVENTS      "{slots,topdown-retiring,topdown-bad-spec,topdown-fe-bound,topdown-be-bound}"
> +#define TOPDOWN_L2_EVENTS      "{slots,topdown-retiring,topdown-bad-spec,topdown-fe-bound,topdown-be-bound,topdown-heavy-ops,topdown-br-mispredict,topdown-fetch-lat,topdown-mem-bound}"
>
>  int arch_evlist__add_default_attrs(struct evlist *evlist)
>  {
>         if (!pmu_have_event("cpu", "slots"))
>                 return 0;
>
> -       return parse_events(evlist, TOPDOWN_L1_EVENTS, NULL);
> +       if (pmu_have_event("cpu", "topdown-heavy-ops"))
> +               return parse_events(evlist, TOPDOWN_L2_EVENTS, NULL);
> +       else
> +               return parse_events(evlist, TOPDOWN_L1_EVENTS, NULL);
>  }
> diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
> index 5a830ae..a5e93d4 100644
> --- a/tools/perf/builtin-stat.c
> +++ b/tools/perf/builtin-stat.c
> @@ -154,6 +154,8 @@ static const char *topdown_metric_L2_attrs[] = {
>         NULL,
>  };
>
> +#define TOPDOWN_MAX_LEVEL                      2
> +
>  static const char *smi_cost_attrs = {
>         "{"
>         "msr/aperf/,"
> @@ -1924,6 +1926,7 @@ static int add_default_attributes(void)
>                 if (evlist__add_default_attrs(evsel_list, default_attrs1) < 0)
>                         return -1;
>
> +               stat_config.topdown_level = TOPDOWN_MAX_LEVEL;
>                 if (arch_evlist__add_default_attrs(evsel_list) < 0)
>                         return -1;
>         }
> --
> 2.7.4
>