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authorArnaldo Carvalho de Melo <acme@redhat.com>2016-04-27 10:16:24 -0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2016-04-27 10:29:07 -0300
commit4cb93446c587d56e2a54f4f83113daba2c0b6dee (patch)
treea251b1d510831dc071eadbbbe3e38a85fe643365 /tools/perf/perf.c
parentc5dfd78eb79851e278b7973031b9ca363da87a7e (diff)
downloadlinux-4cb93446c587d56e2a54f4f83113daba2c0b6dee.tar.gz
perf tools: Set the maximum allowed stack from /proc/sys/kernel/perf_event_max_stack
There is an upper limit to what tooling considers a valid callchain, and it was tied to the hardcoded value in the kernel, PERF_MAX_STACK_DEPTH (127), now that this can be tuned via a sysctl, make it read it and use that as the upper limit, falling back to PERF_MAX_STACK_DEPTH for kernels where this sysctl isn't present. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Brendan Gregg <brendan.d.gregg@gmail.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Milian Wolff <milian.wolff@kdab.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Wang Nan <wangnan0@huawei.com> Link: http://lkml.kernel.org/n/tip-yjqsd30nnkogvj5oyx9ghir9@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/perf.c')
-rw-r--r--tools/perf/perf.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/tools/perf/perf.c b/tools/perf/perf.c
index 7b2df2b46525..83ffe7cd7330 100644
--- a/tools/perf/perf.c
+++ b/tools/perf/perf.c
@@ -17,6 +17,7 @@
#include <subcmd/parse-options.h>
#include "util/bpf-loader.h"
#include "util/debug.h"
+#include <api/fs/fs.h>
#include <api/fs/tracing_path.h>
#include <pthread.h>
#include <stdlib.h>
@@ -533,6 +534,7 @@ int main(int argc, const char **argv)
{
const char *cmd;
char sbuf[STRERR_BUFSIZE];
+ int value;
/* libsubcmd init */
exec_cmd_init("perf", PREFIX, PERF_EXEC_PATH, EXEC_PATH_ENVIRONMENT);
@@ -542,6 +544,9 @@ int main(int argc, const char **argv)
page_size = sysconf(_SC_PAGE_SIZE);
cacheline_size = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);
+ if (sysctl__read_int("kernel/perf_event_max_stack", &value) == 0)
+ sysctl_perf_event_max_stack = value;
+
cmd = extract_argv0_path(argv[0]);
if (!cmd)
cmd = "perf-help";