Commit-ID: 0a2138b28fd56eeb3852133691c881409885ee3f Gitweb: http://git.kernel.org/tip/0a2138b28fd56eeb3852133691c881409885ee3f Author: Arnaldo Carvalho de Melo <a...@redhat.com> AuthorDate: Fri, 12 Dec 2014 16:07:47 -0300 Committer: Arnaldo Carvalho de Melo <a...@redhat.com> CommitDate: Tue, 16 Dec 2014 13:38:26 -0300
perf evlist: Fixup brown paper bag on "hint" for --mmap-pages cmdline arg When failing due to asking for a number of mmap pages that is more than the max, it was suggesting that an even bigger number of mmap pages should be specified, doh, au contraire! Before: [acme@ssdandy linux]$ trace -m 128 usleep 1 Error: Operation not permitted. Hint: Check /proc/sys/kernel/perf_event_mlock_kb (516 kB) setting. Hint: Tried using 516 kB. Hint: Try using a bigger -m/--mmap-pages value. [acme@ssdandy linux]$ After: [acme@ssdandy linux]$ trace -m 128 usleep 1 Error: Operation not permitted. Hint: Check /proc/sys/kernel/perf_event_mlock_kb (516 kB) setting. Hint: Tried using 516 kB. Hint: Try using a smaller -m/--mmap-pages value. [acme@ssdandy linux]$ And to (really) clarify what happens above, when what the user requests is <= max and even then it fails, a changeset is being made to tell that this is a per user limit, not per process (in the above example there was another 'perf trace' running for this user, which was using all the pages it could use). Cc: Adrian Hunter <adrian.hun...@intel.com> Cc: Borislav Petkov <b...@suse.de> Cc: David Ahern <dsah...@gmail.com> Cc: Don Zickus <dzic...@redhat.com> Cc: Frederic Weisbecker <fweis...@gmail.com> Cc: Jiri Olsa <jo...@redhat.com> Cc: Mike Galbraith <efa...@gmx.de> Cc: Namhyung Kim <namhy...@kernel.org> Cc: Paul Mackerras <pau...@samba.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Stephane Eranian <eran...@google.com> Link: http://lkml.kernel.org/n/tip-8qope8lxb898narnq5kmu...@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- tools/perf/util/evlist.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index bb5dfc5..de7515d 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -1495,7 +1495,7 @@ int perf_evlist__strerror_mmap(struct perf_evlist *evlist, int err, char *buf, s scnprintf(buf, size, "Error:\t%s.\n" "Hint:\tCheck /proc/sys/kernel/perf_event_mlock_kb (%d kB) setting.\n" "Hint:\tTried using %zd kB.\n" - "Hint:\tTry using a bigger -m/--mmap-pages value.", + "Hint:\tTry using a smaller -m/--mmap-pages value.", emsg, value, evlist->mmap_len / 1024); break; default: -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
