From fa1332a8011eebe1feefded19c94dcfdb22aacef Mon Sep 17 00:00:00 2001
From: Ravi Bangoria <ravi.bangoria@amd.com>
Date: Tue, 29 Apr 2025 03:59:37 +0000
Subject: 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>
---
 tools/perf/tests/shell/test_data_symbol.sh | 29 ++++++++++++++++++++++++++---
 1 file changed, 26 insertions(+), 3 deletions(-)

(limited to 'tools/perf/tests/shell')

diff --git a/tools/perf/tests/shell/test_data_symbol.sh b/tools/perf/tests/shell/test_data_symbol.sh
index bbe8277496ae..d61b5659a46d 100755
--- a/tools/perf/tests/shell/test_data_symbol.sh
+++ b/tools/perf/tests/shell/test_data_symbol.sh
@@ -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}"
-- 
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