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| author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2014-12-12 20:25:33 +0100 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2014-12-16 17:38:26 +0100 |
| commit | e965bea1ad1a8062b306f7fcc5c3e05dc5213b7c (patch) | |
| tree | d22afdd1269531177ce19cea4250ca3506541127 /tools | |
| parent | perf evlist: Clarify sterror_mmap variable names (diff) | |
| download | linux-e965bea1ad1a8062b306f7fcc5c3e05dc5213b7c.tar.xz linux-e965bea1ad1a8062b306f7fcc5c3e05dc5213b7c.zip | |
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.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-yqdie3c8qvdgenwleri267d4@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/perf/util/evlist.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index d661f252b891..7847f3885081 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); |