Re: [PATCH v5 2/2] perf pmu intel: Adjust cpumaks for sub-NUMA clusters on Emeraldrapids

[Chun-Tse Shao]

Thanks, submitted v6 patch:
lore.kernel.org/20260515172710.428474-1-ctshao@xxxxxxxxxx
I also added SPR into SNC2 in that patch.

-CT

On Thu, Apr 9, 2026 at 9:43 PM Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
>
> On Tue, Apr 07, 2026 at 01:38:43PM -0700, Chun-Tse Shao wrote:
> > Similar to GNR [1], Emeraldrapids supports sub-NUMA clusters as well.
> > Adjust cpumasks as the logic for GNR in [1].
> >
> > Tested on Emeraldrapids with SNC2 enabled:
> >   $ perf stat --per-node -e 'UNC_CHA_CLOCKTICKS,UNC_M_CLOCKTICKS' -a -- sleep 1
> >
> >    Performance counter stats for 'system wide':
> >
> >   N0       30        72125876670      UNC_CHA_CLOCKTICKS
> >   N0        4         8815163648      UNC_M_CLOCKTICKS
> >   N1       30        72124958844      UNC_CHA_CLOCKTICKS
> >   N1        4         8815014974      UNC_M_CLOCKTICKS
> >   N2       30        72121049022      UNC_CHA_CLOCKTICKS
> >   N2        4         8814592626      UNC_M_CLOCKTICKS
> >   N3       30        72117133854      UNC_CHA_CLOCKTICKS
> >   N3        4         8814012840      UNC_M_CLOCKTICKS
> >
> >          1.001574118 seconds time elapsed
> >
> > [1] lore.kernel.org/20250515181417.491401-1-irogers@xxxxxxxxxx
> >
> > Reviewed-by: Zide Chen <zide.chen@xxxxxxxxx>
> > Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>
> > Signed-off-by: Chun-Tse Shao <ctshao@xxxxxxxxxx>
> > ---
> >  tools/perf/arch/x86/util/pmu.c | 56 +++++++++++++++++++++++-----------
> >  1 file changed, 38 insertions(+), 18 deletions(-)
> >
> > diff --git a/tools/perf/arch/x86/util/pmu.c b/tools/perf/arch/x86/util/pmu.c
> > index 938be36ec0f7..3743f5145505 100644
> > --- a/tools/perf/arch/x86/util/pmu.c
> > +++ b/tools/perf/arch/x86/util/pmu.c
> > @@ -30,8 +30,9 @@ static bool x86__is_snc_supported(void)
> >
> >       if (!checked_if_snc_supported) {
> >
> > -             /* Graniterapids supports SNC configuration. */
> > +             /* Emeraldrapids Graniterapids support SNC configuration. */
> >               static const char *const supported_cpuids[] = {
> > +                     "GenuineIntel-6-CF", /* Emeraldrapids */
> >                       "GenuineIntel-6-A[DE]", /* Graniterapids */
>
> It'd be great if we can share these string literals..
>
>
> >               };
> >               char *cpuid = get_cpuid_str((struct perf_cpu){0});
> > @@ -141,23 +142,42 @@ static int uncore_imc_snc(struct perf_pmu *pmu)
> >       // Compute the IMC SNC using lookup tables.
> >       unsigned int imc_num;
> >       int snc_nodes = snc_nodes_per_l3_cache();
> > -     const u8 snc2_map[] = {1, 1, 0, 0};
> > -     const u8 snc3_map[] = {1, 1, 0, 0, 2, 2};
> > -     const u8 *snc_map;
> > -     size_t snc_map_len;
> > -
> > -     switch (snc_nodes) {
> > -     case 2:
> > -             snc_map = snc2_map;
> > -             snc_map_len = ARRAY_SIZE(snc2_map);
> > -             break;
> > -     case 3:
> > -             snc_map = snc3_map;
> > -             snc_map_len = ARRAY_SIZE(snc3_map);
> > -             break;
> > -     default:
> > -             /* Error or no lookup support for SNC with >3 nodes. */
> > -             return 0;
> > +     char *cpuid;
> > +     static const u8 emr_snc2_map[] = { 0, 0, 1, 1 };
> > +     static const u8 gnr_snc2_map[] = { 1, 1, 0, 0 };
> > +     static const u8 snc3_map[] = { 1, 1, 0, 0, 2, 2 };
> > +     static const u8 *snc_map;
> > +     static size_t snc_map_len;
> > +
> > +     /* snc_map is not inited yet. We only look up once to avoid expensive operations. */
> > +     if (!snc_map) {
> > +             switch (snc_nodes) {
> > +             case 2:
> > +                     cpuid = get_cpuid_str((struct perf_cpu){ 0 });
> > +                     if (cpuid) {
> > +                             if (strcmp_cpuid_str("GenuineIntel-6-CF", cpuid) == 0) {
> > +                                     snc_map = emr_snc2_map;
> > +                                     snc_map_len = ARRAY_SIZE(emr_snc2_map);
> > +                             } else if (strcmp_cpuid_str("GenuineIntel-6-A[DE]", cpuid) == 0) {
> > +                                     snc_map = gnr_snc2_map;
> > +                                     snc_map_len = ARRAY_SIZE(gnr_snc2_map);
>
> ... in here as well.
>
> Thanks,
> Namhyung
>
>
> > +                             }
> > +                             free(cpuid);
> > +                     }
> > +                     break;
> > +             case 3:
> > +                     snc_map = snc3_map;
> > +                     snc_map_len = ARRAY_SIZE(snc3_map);
> > +                     break;
> > +             default:
> > +                     /* Error or no lookup support for SNC with >3 nodes. */
> > +                     return 0;
> > +             }
> > +
> > +             if (!snc_map) {
> > +                     pr_warning("Unexpected: can not find snc map config");
> > +                     return 0;
> > +             }
> >       }
> >
> >       /* Compute SNC for PMU. */
> > --
> > 2.53.0.1213.gd9a14994de-goog
> >