Messages in this thread Patch in this message | | | From | Arnaldo Carvalho de Melo <> | Subject | [PATCH 06/15] perf: builtin-record: Provide advice if mmap'ing fails with EPERM. | Date | Fri, 23 Dec 2011 19:53:09 -0200 |
| |
From: Nelson Elhage <nelhage@nelhage.com>
This failure is most likely due to running up against the kernel.perf_event_mlock_kb sysctl, so we can tell the user what to do to fix the issue.
Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1324301972-22740-3-git-send-email-nelhage@nelhage.com Signed-off-by: Nelson Elhage <nelhage@nelhage.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> --- tools/perf/builtin-record.c | 9 ++++++++- 1 files changed, 8 insertions(+), 1 deletions(-)
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c index f8fd14f..56bb447 100644 --- a/tools/perf/builtin-record.c +++ b/tools/perf/builtin-record.c @@ -272,8 +272,15 @@ try_again: exit(-1); } - if (perf_evlist__mmap(evlist, opts->mmap_pages, false) < 0) + if (perf_evlist__mmap(evlist, opts->mmap_pages, false) < 0) { + if (errno == EPERM) + die("Permission error mapping pages.\n" + "Consider increasing " + "/proc/sys/kernel/perf_event_mlock_kb,\n" + "or try again with a smaller value of -m/--mmap_pages.\n" + "(current value: %d)\n", opts->mmap_pages); die("failed to mmap with %d (%s)\n", errno, strerror(errno)); + } if (rec->file_new) session->evlist = evlist; -- 1.7.8.rc0.35.gee6df
| |