From: Kim Phillips <kim.phillips@amd.com>
Date: Tue, 8 Sep 2020 16:47:34 -0500
Subject: perf/amd/uncore: Set all slices and threads to restore perf stat -a
behaviour
Git-commit: c8fe99d0701fec9fb849ec880a86bc5592530496
Patch-mainline: v5.10-rc1
References: jsc#SLE-16756
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
...
Fixes: 2f217d58a8a0 ("perf/x86/amd/uncore: Set the thread mask for F17h L3 PMCs")
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20200908214740.18097-2-kim.phillips@amd.com
Acked-by: Borislav Petkov <bp@suse.de>
---
arch/x86/events/amd/uncore.c | 26 ++++++++------------------
1 file changed, 8 insertions(+), 18 deletions(-)
--- a/arch/x86/events/amd/uncore.c
+++ b/arch/x86/events/amd/uncore.c
@@ -181,26 +181,16 @@ static void amd_uncore_del(struct perf_e
}
/*
- * 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);
- int thread = 2 * (cpu_data(cpu).cpu_core_id % 4);
- unsigned int shift;
-
- 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);
+ if (boot_cpu_data.x86 <= 0x18)
+ return AMD64_L3_SLICE_MASK | AMD64_L3_THREAD_MASK;
- 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)
@@ -230,7 +220,7 @@ static int amd_uncore_event_init(struct
* 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)