Commit-ID: e965bea1ad1a8062b306f7fcc5c3e05dc5213b7c Gitweb: http://git.kernel.org/tip/e965bea1ad1a8062b306f7fcc5c3e05dc5213b7c Author: Arnaldo Carvalho de Melo <a...@redhat.com> AuthorDate: Fri, 12 Dec 2014 16:25:33 -0300 Committer: Arnaldo Carvalho de Melo <a...@redhat.com> CommitDate: Tue, 16 Dec 2014 13:38:26 -0300
perf evlist: Improve the strerror_mmap method Considering the per user locked pages limit, improve the message when a user uses multiple simultaneous perf mmap calls: When the request is more than the current maximum: [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 'sudo sh -c "echo 1032 > /proc/sys/kernel/perf_event_mlock_kb"', or Hint: Try using a smaller -m/--mmap-pages value. [acme@ssdandy linux]$ And when the limit is less than that: [acme@ssdandy linux]$ trace -m 512 usleep 1 Error: Operation not permitted. Hint: Check /proc/sys/kernel/perf_event_mlock_kb (2056 kB) setting. Hint: Tried using 2052 kB. Hint: Try using a smaller -m/--mmap-pages value. [acme@ssdandy linux]$ 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-yqdie3c8qvdgenwleri26...@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <a...@redhat.com> --- tools/perf/util/evlist.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index d661f25..7847f38 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -1487,16 +1487,25 @@ int perf_evlist__strerror_open(struct perf_evlist *evlist __maybe_unused, int perf_evlist__strerror_mmap(struct perf_evlist *evlist, int err, char *buf, size_t size) { char sbuf[STRERR_BUFSIZE], *emsg = strerror_r(err, sbuf, sizeof(sbuf)); - int pages_attempted = evlist->mmap_len / 1024, pages_max_per_user; + int pages_attempted = evlist->mmap_len / 1024, pages_max_per_user, printed = 0; switch (err) { case EPERM: sysctl__read_int("kernel/perf_event_mlock_kb", &pages_max_per_user); - scnprintf(buf, size, "Error:\t%s.\n" + printed += scnprintf(buf + printed, size - printed, + "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 smaller -m/--mmap-pages value.", + "Hint:\tTried using %zd kB.\n", emsg, pages_max_per_user, pages_attempted); + + if (pages_attempted >= pages_max_per_user) { + printed += scnprintf(buf + printed, size - printed, + "Hint:\tTry 'sudo sh -c \"echo %d > /proc/sys/kernel/perf_event_mlock_kb\"', or\n", + pages_max_per_user + pages_attempted); + } + + printed += scnprintf(buf + printed, size - printed, + "Hint:\tTry using a smaller -m/--mmap-pages value."); break; default: scnprintf(buf, size, "%s", emsg); -- 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/
