diff options
| author | Sandipan Das <sandipan.das@amd.com> | 2023-10-05 07:23:13 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2023-10-09 16:12:24 +0200 |
| commit | 7ef0343855dc23a979a53b3143540f93f3e5bef8 (patch) | |
| tree | 5990c6b7081bc48851695b575801dbd2354a5dd6 /arch/x86/events/amd | |
| parent | perf/x86/amd/uncore: Move discovery and registration (diff) | |
| download | linux-7ef0343855dc23a979a53b3143540f93f3e5bef8.tar.xz linux-7ef0343855dc23a979a53b3143540f93f3e5bef8.zip | |
perf/x86/amd/uncore: Use rdmsr if rdpmc is unavailable
Not all uncore PMUs may support the use of the RDPMC instruction for
reading counters. In such cases, read the count from the corresponding
PERF_CTR register using the RDMSR instruction.
Signed-off-by: Sandipan Das <sandipan.das@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/e9d994e32a3fcb39fa59fcf43ab4260d11aba097.1696425185.git.sandipan.das@amd.com
Diffstat (limited to 'arch/x86/events/amd')
| -rw-r--r-- | arch/x86/events/amd/uncore.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c index ff1d09cc07ad..2fe623923034 100644 --- a/arch/x86/events/amd/uncore.c +++ b/arch/x86/events/amd/uncore.c @@ -96,7 +96,16 @@ static void amd_uncore_read(struct perf_event *event) */ prev = local64_read(&hwc->prev_count); - rdpmcl(hwc->event_base_rdpmc, new); + + /* + * Some uncore PMUs do not have RDPMC assignments. In such cases, + * read counts directly from the corresponding PERF_CTR. + */ + if (hwc->event_base_rdpmc < 0) + rdmsrl(hwc->event_base, new); + else + rdpmcl(hwc->event_base_rdpmc, new); + local64_set(&hwc->prev_count, new); delta = (new << COUNTER_SHIFT) - (prev << COUNTER_SHIFT); delta >>= COUNTER_SHIFT; @@ -164,6 +173,9 @@ out: hwc->event_base_rdpmc = pmu->rdpmc_base + hwc->idx; hwc->state = PERF_HES_UPTODATE | PERF_HES_STOPPED; + if (pmu->rdpmc_base < 0) + hwc->event_base_rdpmc = -1; + if (flags & PERF_EF_START) event->pmu->start(event, PERF_EF_RELOAD); |