lkml.org 
[lkml]   [2014]   [Dec]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 18/18] perf trace: Provide a better explanation when mmap fails
Date
From: Arnaldo Carvalho de Melo <acme@redhat.com>

If we ask for a mmap lenght than the max configured via the relevant
sysctl, provide a better warning, instead of just expanding the EPERM
returned:

[acme@ssdandy ~]$ trace -m 256 -e nanosleep sleep 2
Error: Operation not permitted.
Hint: Check /proc/sys/kernel/perf_event_mlock_kb (516 kB) setting.
Hint: Tried using 1028 kB.
Hint: Try using a bigger -m/--mmap-pages value.

[acme@ssdandy ~]$ trace -m 128 -e nanosleep sleep 2
2001.280 (2000.403 ms): nanosleep(rqtp: 0x7fff89a8a7f0) = 0
[acme@ssdandy ~]$

An upcoming patch will autotune the request for non-root users when -m
is not used.

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-cdvxfz2gycetbkopm9sna1qp@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/builtin-trace.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 83a4835c8118..327541e43c7f 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -2045,7 +2045,6 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
unsigned long before;
const bool forks = argc > 0;
bool draining = false;
- char sbuf[STRERR_BUFSIZE];

trace->live = true;

@@ -2106,11 +2105,8 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
goto out_error_open;

err = perf_evlist__mmap(evlist, trace->opts.mmap_pages, false);
- if (err < 0) {
- fprintf(trace->output, "Couldn't mmap the events: %s\n",
- strerror_r(errno, sbuf, sizeof(sbuf)));
- goto out_delete_evlist;
- }
+ if (err < 0)
+ goto out_error_mmap;

perf_evlist__enable(evlist);

@@ -2210,6 +2206,10 @@ out_error_tp:
perf_evlist__strerror_tp(evlist, errno, errbuf, sizeof(errbuf));
goto out_error;

+out_error_mmap:
+ perf_evlist__strerror_mmap(evlist, errno, errbuf, sizeof(errbuf));
+ goto out_error;
+
out_error_open:
perf_evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));

--
1.9.3


\
 
 \ /
  Last update: 2014-12-11 23:01    [W:0.089 / U:1.188 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site