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perf mem/c2c amd: Add ldlat support

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'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>
This commit is contained in:
Ravi Bangoria
2025-04-29 03:59:37 +00:00
committed by Arnaldo Carvalho de Melo
parent fc481adc97
commit fa1332a801
8 changed files with 83 additions and 10 deletions
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29
tools/perf/tests/shell/test_data_symbol.sh
View File

@@ -54,11 +54,34 @@ trap cleanup_files exit term int
echo "Recording workload..."
# perf mem/c2c internally uses IBS PMU on AMD CPU which doesn't support
# user/kernel filtering and per-process monitoring, spin program on
# specific CPU and test in per-CPU mode.
is_amd=$(grep -E -c 'vendor_id.*AuthenticAMD' /proc/cpuinfo)
if (($is_amd >= 1)); then
mem_events="$(perf mem record -v -e list 2>&1)"
if ! [[ "$mem_events" =~ ^mem\-ldst.*ibs_op/(.*)/.*available ]]; then
echo "ERROR: mem-ldst event is not matching"
exit 1
fi
# --ldlat on AMD:
# o Zen4 and earlier uarch does not support ldlat
# o Even on supported platforms, it's disabled (--ldlat=0) by default.
ldlat=${BASH_REMATCH[1]}
if [[ -n $ldlat ]]; then
if ! [[ "$ldlat" =~ ldlat=0 ]]; then
echo "ERROR: ldlat not initialized to 0?"
exit 1
fi
mem_events="$(perf mem record -v --ldlat=150 -e list 2>&1)"
if ! [[ "$mem_events" =~ ^mem-ldst.*ibs_op/ldlat=150/.*available ]]; then
echo "ERROR: --ldlat not honored?"
exit 1
fi
fi
# perf mem/c2c internally uses IBS PMU on AMD CPU which doesn't
# support user/kernel filtering and per-process monitoring on older
# kernels, spin program on specific CPU and test in per-CPU mode.
perf mem record -vvv -o ${PERF_DATA} -C 0 -- taskset -c 0 $TEST_PROGRAM 2>"${ERR_FILE}"
else
perf mem record -vvv --all-user -o ${PERF_DATA} -- $TEST_PROGRAM 2>"${ERR_FILE}"