Commit 2f217d58a8a0 ("perf/x86/amd/uncore: Set the thread mask for F17h L3 PMCs") inadvertently changed the uncore driver's behaviour wrt perf tool invocations with or without a CPU list, specified with -C / --cpu=.
Change the behaviour of the driver to assume the former all-cpu (-a) case, which is the more commonly desired default. This fixes '-a -A' invocations without explicit cpu lists (-C) to not count L3 events only on behalf of the first thread of the first core in the L3 domain.
BEFORE:
Activity performed by the first thread of the last core (CPU#43) in CPU#40's L3 domain is not reported by CPU#40:
sudo perf stat -a -A -e l3_request_g1.caching_l3_cache_accesses taskset -c 43 perf bench mem memcpy -s 32mb -l 100 -f default ... CPU36 21,835 l3_request_g1.caching_l3_cache_accesses CPU40 87,066 l3_request_g1.caching_l3_cache_accesses CPU44 17,360 l3_request_g1.caching_l3_cache_accesses ...
AFTER:
The L3 domain activity is now reported by CPU#40:
sudo perf stat -a -A -e l3_request_g1.caching_l3_cache_accesses taskset -c 43 perf bench mem memcpy -s 32mb -l 100 -f default ... CPU36 354,891 l3_request_g1.caching_l3_cache_accesses CPU40 1,780,870 l3_request_g1.caching_l3_cache_accesses CPU44 315,062 l3_request_g1.caching_l3_cache_accesses ...
Reported-by: Stephane Eranian eranian@google.com Signed-off-by: Kim Phillips kim.phillips@amd.com Fixes: 2f217d58a8a0 ("perf/x86/amd/uncore: Set the thread mask for F17h L3 PMCs") Cc: Stephane Eranian eranian@google.com Cc: Peter Zijlstra peterz@infradead.org Cc: Ingo Molnar mingo@kernel.org Cc: Ingo Molnar mingo@redhat.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Borislav Petkov bp@alien8.de Cc: Alexander Shishkin alexander.shishkin@linux.intel.com Cc: Arnaldo Carvalho de Melo acme@kernel.org Cc: "H. Peter Anvin" hpa@zytor.com Cc: Jiri Olsa jolsa@redhat.com Cc: Mark Rutland mark.rutland@arm.com Cc: Michael Petlan mpetlan@redhat.com Cc: Namhyung Kim namhyung@kernel.org Cc: LKML linux-kernel@vger.kernel.org Cc: x86 x86@kernel.org Cc: stable@vger.kernel.org --- Original submission:
https://lore.kernel.org/lkml/20200323233159.19601-1-kim.phillips@amd.com/
arch/x86/events/amd/uncore.c | 28 ++++++++-------------------- 1 file changed, 8 insertions(+), 20 deletions(-)
diff --git a/arch/x86/events/amd/uncore.c b/arch/x86/events/amd/uncore.c index 76400c052b0e..e7e61c8b56bd 100644 --- a/arch/x86/events/amd/uncore.c +++ b/arch/x86/events/amd/uncore.c @@ -181,28 +181,16 @@ static void amd_uncore_del(struct perf_event *event, int flags) }
/* - * Convert logical CPU number to L3 PMC Config ThreadMask format + * Return a full thread and slice mask until per-CPU is + * properly supported. */ -static u64 l3_thread_slice_mask(int cpu) +static u64 l3_thread_slice_mask(void) { - u64 thread_mask, core = topology_core_id(cpu); - unsigned int shift, thread = 0; + if (boot_cpu_data.x86 <= 0x18) + return AMD64_L3_SLICE_MASK | AMD64_L3_THREAD_MASK;
- if (topology_smt_supported() && !topology_is_primary_thread(cpu)) - thread = 1; - - if (boot_cpu_data.x86 <= 0x18) { - shift = AMD64_L3_THREAD_SHIFT + 2 * (core % 4) + thread; - thread_mask = BIT_ULL(shift); - - return AMD64_L3_SLICE_MASK | thread_mask; - } - - core = (core << AMD64_L3_COREID_SHIFT) & AMD64_L3_COREID_MASK; - shift = AMD64_L3_THREAD_SHIFT + thread; - thread_mask = BIT_ULL(shift); - - return AMD64_L3_EN_ALL_SLICES | core | thread_mask; + return AMD64_L3_EN_ALL_SLICES | AMD64_L3_EN_ALL_CORES | + AMD64_L3_F19H_THREAD_MASK; }
static int amd_uncore_event_init(struct perf_event *event) @@ -232,7 +220,7 @@ static int amd_uncore_event_init(struct perf_event *event) * For other events, the two fields do not affect the count. */ if (l3_mask && is_llc_event(event)) - hwc->config |= l3_thread_slice_mask(event->cpu); + hwc->config |= l3_thread_slice_mask();
uncore = event_to_amd_uncore(event); if (!uncore)