linux-kernel - [PATCH v2] perf mem: Fix printing PERF_MEM_LVLNUM_{L2

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Message-ID: <20240926144040.77897-1-thomas.falcon@intel.com>
Date: Thu, 26 Sep 2024 09:40:40 -0500
From: Thomas Falcon <thomas.falcon@...el.com>
To: peterz@...radead.org,
	mingo@...hat.com,
	acme@...nel.org,
	namhyung@...nel.org,
	mark.rutland@....com,
	alexander.shishkin@...ux.intel.com,
	jolsa@...nel.org,
	irogers@...gle.com,
	adrian.hunter@...el.com,
	kan.liang@...ux.intel.com
Cc: linux-perf-users@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	leo.yan@....com,
	Thomas Falcon <thomas.falcon@...el.com>
Subject: [PATCH v2] perf mem: Fix printing PERF_MEM_LVLNUM_{L2_MHB|MSC}

With commit 8ec9497d3ef34 ("tools/include: Sync uapi/linux/perf.h
with the kernel sources"), 'perf mem report' gives an incorrect memory
access string.
...
0.02%	1	3644	L5 hit	[.] 0x0000000000009b0e	mlc	[.] 0x00007fce43f59480
...

This occurs because, if no entry exists in mem_lvlnum, perf_mem__lvl_scnprintf
will default to 'L%d, lvl', which in this case for PERF_MEM_LVLNUM_L2_MHB is 0x05.
Add entries for PERF_MEM_LVLNUM_L2_MHB and PERF_MEM_LVLNUM_MSC to mem_lvlnum,
so that the correct strings are printed.
...
0.02%	1	3644	L2 MHB hit	[.] 0x0000000000009b0e	mlc	[.] 0x00007fce43f59480
...

Fixes: 8ec9497d3ef34 ("tools/include: Sync uapi/linux/perf.h with the kernel sources")
Suggested-by: Kan Liang <kan.liang@...ux.intel.com>
Signed-off-by: Thomas Falcon <thomas.falcon@...el.com>
Reviewed-by: Kan Liang <kan.liang@...ux.intel.com>
---
v2: Leo Yan suggested adding PERF_MEM_LVLNUM_L{1-4} to mem_lvlnum
    and printing a clearer message in the case of an unknown level
    to more easily catch similar issues in the future
---
 tools/perf/util/mem-events.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/mem-events.c b/tools/perf/util/mem-events.c
index 051feb93ed8d..bf5090f5220b 100644
--- a/tools/perf/util/mem-events.c
+++ b/tools/perf/util/mem-events.c
@@ -366,6 +366,12 @@ static const char * const mem_lvl[] = {
 };
 
 static const char * const mem_lvlnum[] = {
+	[PERF_MEM_LVLNUM_L1] = "L1",
+	[PERF_MEM_LVLNUM_L2] = "L2",
+	[PERF_MEM_LVLNUM_L3] = "L3",
+	[PERF_MEM_LVLNUM_L4] = "L4",
+	[PERF_MEM_LVLNUM_L2_MHB] = "L2 MHB",
+	[PERF_MEM_LVLNUM_MSC] = "Memory-side Cache",
 	[PERF_MEM_LVLNUM_UNC] = "Uncached",
 	[PERF_MEM_LVLNUM_CXL] = "CXL",
 	[PERF_MEM_LVLNUM_IO] = "I/O",
@@ -448,7 +454,7 @@ int perf_mem__lvl_scnprintf(char *out, size_t sz, const struct mem_info *mem_inf
 		if (mem_lvlnum[lvl])
 			l += scnprintf(out + l, sz - l, mem_lvlnum[lvl]);
 		else
-			l += scnprintf(out + l, sz - l, "L%d", lvl);
+			l += scnprintf(out + l, sz - l, "Unknown level %d", lvl);
 
 		l += scnprintf(out + l, sz - l, " %s", hit_miss);
 		return l;
-- 
2.46.0