linux-kernel - [PATCH 5.2 164/413] perf tools: Increase MAX_NR_CPUS and MAX

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Message-Id: <20190724191746.787421443@linuxfoundation.org>
Date:   Wed, 24 Jul 2019 21:17:35 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Kyle Meyer <kyle.meyer@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.2 164/413] perf tools: Increase MAX_NR_CPUS and MAX_CACHES

[ 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@....com>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Link: http://lkml.kernel.org/r/20190620193630.154025-1-meyerk@stormcage.eag.rdlabs.hpecorp.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.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 d59dee61b64d..a26555baf692 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 fb0aa661644b..b82d4577d969 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