diff options
| author | Ravi Bangoria <ravi.bangoria@amd.com> | 2025-04-29 03:59:37 +0000 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2025-04-29 22:30:46 -0300 |
| commit | fa1332a8011eebe1feefded19c94dcfdb22aacef (patch) | |
| tree | 79665768767c07493fbd52f7899526596fdee4b8 /tools/perf/Documentation | |
| parent | fc481adc97f45328e242b6dba9fabd24f2082a6e (diff) | |
perf mem/c2c amd: Add ldlat support
'perf mem/c2c' uses IBS Op PMU on AMD platforms.
IBS Op PMU on Zen5 uarch has added support for Load Latency filtering.
Implement 'perf mem/c2c' --ldlat using IBS Op Load Latency filtering
capability.
Some subtle differences between AMD and other arch:
o --ldlat is disabled by default on AMD
o Supported values are 128 to 2048.
Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Ananth Narayan <ananth.narayan@amd.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Joe Mario <jmario@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sandipan Das <sandipan.das@amd.com>
Cc: Santosh Shukla <santosh.shukla@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20250429035938.1301-4-ravi.bangoria@amd.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/Documentation')
| -rw-r--r-- | tools/perf/Documentation/perf-c2c.txt | 11 | ||||
| -rw-r--r-- | tools/perf/Documentation/perf-mem.txt | 13 |
2 files changed, 20 insertions, 4 deletions
diff --git a/tools/perf/Documentation/perf-c2c.txt b/tools/perf/Documentation/perf-c2c.txt index 856f0dfb8e5a3..f4af2dd6ab318 100644 --- a/tools/perf/Documentation/perf-c2c.txt +++ b/tools/perf/Documentation/perf-c2c.txt @@ -54,8 +54,15 @@ RECORD OPTIONS -l:: --ldlat:: - Configure mem-loads latency. Supported on Intel and Arm64 processors - only. Ignored on other archs. + Configure mem-loads latency. Supported on Intel, Arm64 and some AMD + processors. Ignored on other archs. + + On supported AMD processors: + - /sys/bus/event_source/devices/ibs_op/caps/ldlat file contains '1'. + - Supported latency values are 128 to 2048 (both inclusive). + - Latency value which is a multiple of 128 incurs a little less profiling + overhead compared to other values. + - Load latency filtering is disabled by default. -k:: --all-kernel:: diff --git a/tools/perf/Documentation/perf-mem.txt b/tools/perf/Documentation/perf-mem.txt index 8a1bd9ff0f86d..a9e3c71a22055 100644 --- a/tools/perf/Documentation/perf-mem.txt +++ b/tools/perf/Documentation/perf-mem.txt @@ -28,6 +28,8 @@ and kernel support is required. See linkperf:perf-arm-spe[1] for a setup guide. Due to the statistical nature of SPE sampling, not every memory operation will be sampled. +On AMD this use IBS Op PMU to sample load-store operations. + COMMON OPTIONS -------------- -f:: @@ -67,8 +69,15 @@ RECORD OPTIONS Configure all used events to run in user space. --ldlat <n>:: - Specify desired latency for loads event. Supported on Intel and Arm64 - processors only. Ignored on other archs. + Specify desired latency for loads event. Supported on Intel, Arm64 and + some AMD processors. Ignored on other archs. + + On supported AMD processors: + - /sys/bus/event_source/devices/ibs_op/caps/ldlat file contains '1'. + - Supported latency values are 128 to 2048 (both inclusive). + - Latency value which is a multiple of 128 incurs a little less profiling + overhead compared to other values. + - Load latency filtering is disabled by default. REPORT OPTIONS -------------- |