[PATCH v2] x86/events/intel/ds: Enable large PEBS for PERF_SAMPLE_WEIGHT_TYPE

From: Like Xu
Date: Thu May 19 2022 - 11:19:35 EST


From: Like Xu <likexu@xxxxxxxxxxx>

All the information required by the PERF_SAMPLE_WEIGHT is
available in the pebs record. Thus large PEBS could be enabled
for PERF_SAMPLE_WEIGHT sample type to save PMIs overhead until
other non-compatible flags such as PERF_SAMPLE_DATA_PAGE_SIZE
(due to lack of munmap tracking) stop it.

To cover new weight extension, add PERF_SAMPLE_WEIGHT_TYPE
to the guardian LARGE_PEBS_FLAGS.

Tested it with:

$ perf mem record -c 1000 workload
Before: Captured and wrote 0.126 MB perf.data (958 samples) [958 PMIs]
After: Captured and wrote 0.313 MB perf.data (4859 samples) [3 PMIs]

Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Reported-by: Yongchao Duan <yongduan@xxxxxxxxxxx>
Signed-off-by: Like Xu <likexu@xxxxxxxxxxx>
---
v1: https://lore.kernel.org/lkml/20220519104509.51847-1-likexu@xxxxxxxxxxx/
v1 -> v2 Changelog:
- Use the PERF_SAMPLE_WEIGHT_TYPE instead (Kan);

arch/x86/events/perf_event.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index 21a5482bcf84..1ca6200ca135 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -136,7 +136,8 @@ struct amd_nb {
PERF_SAMPLE_DATA_SRC | PERF_SAMPLE_IDENTIFIER | \
PERF_SAMPLE_TRANSACTION | PERF_SAMPLE_PHYS_ADDR | \
PERF_SAMPLE_REGS_INTR | PERF_SAMPLE_REGS_USER | \
- PERF_SAMPLE_PERIOD | PERF_SAMPLE_CODE_PAGE_SIZE)
+ PERF_SAMPLE_PERIOD | PERF_SAMPLE_CODE_PAGE_SIZE | \
+ PERF_SAMPLE_WEIGHT_TYPE)

#define PEBS_GP_REGS \
((1ULL << PERF_REG_X86_AX) | \
--
2.36.1