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... 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)