[PATCH AUTOSEL 5.1 147/219] perf tools: Increase MAX_NR_CPUS and MAX_CACHES

Sasha Levin
2019-07-15T14:12:41Z

From: Kyle Meyer <kyle.meyer@hpe.com>

[ Upstream commit 9f94c7f947e919c343b30f080285af53d0fa9902 ]

Attempting to profile 1024 or more CPUs with perf causes two errors:

perf record -a
[ perf record: Woken up X times to write data ]
way too many cpu caches..
[ perf record: Captured and wrote X MB perf.data (X samples) ]

perf report -C 1024
Error: failed to set cpu bitmap
Requested CPU 1024 too large. Consider raising MAX_NR_CPUS

Increasing MAX_NR_CPUS from 1024 to 2048 and redefining MAX_CACHES as
MAX_NR_CPUS * 4 returns normal functionality to perf:

perf record -a
[ perf record: Woken up X times to write data ]
[ perf record: Captured and wrote X MB perf.data (X samples) ]

perf report -C 1024
...

Signed-off-by: Kyle Meyer <kyle.meyer@hpe.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190620193630.154025-1-meyerk@stormcage.eag.rdlabs.hpecorp.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/perf.h | 2 +-
tools/perf/util/header.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index c59743def8d3..b86ecc7afdd7 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -26,7 +26,7 @@ static inline unsigned long long rdclock(void)
}

#ifndef MAX_NR_CPUS
-#define MAX_NR_CPUS 1024
+#define MAX_NR_CPUS 2048
#endif

extern const char *input_name;
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 682e3d524d3c..df608cfaa03c 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -1100,7 +1100,7 @@ static int build_caches(struct cpu_cache_level caches[], u32 size, u32 *cntp)
return 0;
}

-#define MAX_CACHES 2000
+#define MAX_CACHES (MAX_NR_CPUS * 4)

static int write_cache(struct feat_fd *ff,
struct perf_evlist *evlist __maybe_unused)
--
2.20.1