linux-kernel - [PATCH v2] x86/events/intel/ds: Enable large PEBS for PERF_SAMPLE_WEIGHT

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Message-Id: <20220519151913.80545-1-likexu@tencent.com>
Date:   Thu, 19 May 2022 23:19:13 +0800
From:   Like Xu <like.xu.linux@...il.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Kan Liang <kan.liang@...ux.intel.com>,
        Stephane Eranian <eranian@...gle.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v2] x86/events/intel/ds: Enable large PEBS for PERF_SAMPLE_WEIGHT_TYPE

From: Like Xu <likexu@...cent.com>

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@...ux.intel.com>
Cc: Stephane Eranian <eranian@...gle.com>
Cc: Jiri Olsa <jolsa@...nel.org>
Reported-by: Yongchao Duan <yongduan@...cent.com>
Signed-off-by: Like Xu <likexu@...cent.com>
---
v1: https://lore.kernel.org/lkml/20220519104509.51847-1-likexu@tencent.com/
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