diff options
| author | Kan Liang <kan.liang@linux.intel.com> | 2023-04-21 21:45:28 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2023-05-08 11:58:27 +0300 |
| commit | b752ea0c28e3f7f0aaaad6abf84f735eebc37a60 (patch) | |
| tree | 7c2ce916f21d479c2a3e3ba92fa910a721b8d089 /arch/x86/include/asm/perf_event.h | |
| parent | 90befef5a9e820ccccc33181ec14c015980300cc (diff) | |
| download | linux-b752ea0c28e3f7f0aaaad6abf84f735eebc37a60.tar.xz | |
perf/x86/intel/ds: Flush PEBS DS when changing PEBS_DATA_CFG
Several similar kernel warnings can be triggered,
[56605.607840] CPU0 PEBS record size 0, expected 32, config 0 cpuc->record_size=208
when the below commands are running in parallel for a while on SPR.
while true;
do
perf record --no-buildid -a --intr-regs=AX \
-e cpu/event=0xd0,umask=0x81/pp \
-c 10003 -o /dev/null ./triad;
done &
while true;
do
perf record -o /tmp/out -W -d \
-e '{ld_blocks.store_forward:period=1000000, \
MEM_TRANS_RETIRED.LOAD_LATENCY:u:precise=2:ldlat=4}' \
-c 1037 ./triad;
done
The triad program is just the generation of loads/stores.
The warnings are triggered when an unexpected PEBS record (with a
different config and size) is found.
A system-wide PEBS event with the large PEBS config may be enabled
during a context switch. Some PEBS records for the system-wide PEBS
may be generated while the old task is sched out but the new one
hasn't been sched in yet. When the new task is sched in, the
cpuc->pebs_record_size may be updated for the per-task PEBS events. So
the existing system-wide PEBS records have a different size from the
later PEBS records.
The PEBS buffer should be flushed right before the hardware is
reprogrammed. The new size and threshold should be updated after the
old buffer has been flushed.
Reported-by: Stephane Eranian <eranian@google.com>
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230421184529.3320912-1-kan.liang@linux.intel.com
Diffstat (limited to 'arch/x86/include/asm/perf_event.h')
| -rw-r--r-- | arch/x86/include/asm/perf_event.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h index 8fc15ed5e60b..abf09882f58b 100644 --- a/arch/x86/include/asm/perf_event.h +++ b/arch/x86/include/asm/perf_event.h @@ -121,6 +121,9 @@ #define PEBS_DATACFG_LBRS BIT_ULL(3) #define PEBS_DATACFG_LBR_SHIFT 24 +/* Steal the highest bit of pebs_data_cfg for SW usage */ +#define PEBS_UPDATE_DS_SW BIT_ULL(63) + /* * Intel "Architectural Performance Monitoring" CPUID * detection/enumeration details: |