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author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2010-03-22 13:10:28 -0300 |
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committer | Ingo Molnar <mingo@elte.hu> | 2010-03-22 18:47:35 +0100 |
commit | 084ab9f862416b2ddb4bb9804884de19bf09774d (patch) | |
tree | 3e6bf779f4e7f75da57a381fab2aa9f60316fb01 | |
parent | ca721e45b39209415d2288dbac3667b26d9d1def (diff) | |
download | kernel_samsung_smdk4412-084ab9f862416b2ddb4bb9804884de19bf09774d.tar.gz kernel_samsung_smdk4412-084ab9f862416b2ddb4bb9804884de19bf09774d.tar.bz2 kernel_samsung_smdk4412-084ab9f862416b2ddb4bb9804884de19bf09774d.zip |
perf stat: Better report failure to collect system wide stats
Before:
[acme@doppio linux-2.6-tip]$ perf stat -a sleep 1s
Performance counter stats for 'sleep 1s':
<not counted> task-clock-msecs
<not counted> context-switches
<not counted> CPU-migrations
<not counted> page-faults
<not counted> cycles
<not counted> instructions
<not counted> branches
<not counted> branch-misses
<not counted> cache-references
<not counted> cache-misses
1.016998463 seconds time elapsed
[acme@doppio linux-2.6-tip]$
Now:
[acme@doppio linux-2.6-tip]$ perf stat -a sleep 1s
No permission to collect system-wide stats.
Consider tweaking /proc/sys/kernel/perf_event_paranoid.
[acme@doppio linux-2.6-tip]$
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1269274229-20442-4-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r-- | tools/perf/builtin-stat.c | 39 |
1 files changed, 28 insertions, 11 deletions
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index c92f90ff5a9..1036ca739e6 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -144,10 +144,11 @@ struct stats runtime_branches_stats; #define ERR_PERF_OPEN \ "Error: counter %d, sys_perf_event_open() syscall returned with %d (%s)\n" -static void create_perf_stat_counter(int counter) +static int create_perf_stat_counter(int counter) { struct perf_event_attr *attr = attrs + counter; int thread; + int ncreated = 0; if (scale) attr->read_format = PERF_FORMAT_TOTAL_TIME_ENABLED | @@ -159,9 +160,11 @@ static void create_perf_stat_counter(int counter) for (cpu = 0; cpu < nr_cpus; cpu++) { fd[cpu][counter][0] = sys_perf_event_open(attr, -1, cpumap[cpu], -1, 0); - if (fd[cpu][counter][0] < 0 && verbose) - fprintf(stderr, ERR_PERF_OPEN, counter, - fd[cpu][counter][0], strerror(errno)); + if (fd[cpu][counter][0] < 0) + pr_debug(ERR_PERF_OPEN, counter, + fd[cpu][counter][0], strerror(errno)); + else + ++ncreated; } } else { attr->inherit = inherit; @@ -172,12 +175,16 @@ static void create_perf_stat_counter(int counter) for (thread = 0; thread < thread_num; thread++) { fd[0][counter][thread] = sys_perf_event_open(attr, all_tids[thread], -1, -1, 0); - if (fd[0][counter][thread] < 0 && verbose) - fprintf(stderr, ERR_PERF_OPEN, counter, - fd[0][counter][thread], - strerror(errno)); + if (fd[0][counter][thread] < 0) + pr_debug(ERR_PERF_OPEN, counter, + fd[0][counter][thread], + strerror(errno)); + else + ++ncreated; } } + + return ncreated; } /* @@ -264,7 +271,7 @@ static int run_perf_stat(int argc __used, const char **argv) { unsigned long long t0, t1; int status = 0; - int counter; + int counter, ncreated = 0; int child_ready_pipe[2], go_pipe[2]; const bool forks = (argc > 0); char buf; @@ -324,7 +331,16 @@ static int run_perf_stat(int argc __used, const char **argv) } for (counter = 0; counter < nr_counters; counter++) - create_perf_stat_counter(counter); + ncreated += create_perf_stat_counter(counter); + + if (ncreated == 0) { + pr_err("No permission to collect %sstats.\n" + "Consider tweaking /proc/sys/kernel/perf_event_paranoid.\n", + system_wide ? "system-wide " : ""); + if (child_pid != -1) + kill(child_pid, SIGTERM); + return -1; + } /* * Enable counters and exec the command: @@ -587,7 +603,8 @@ int cmd_stat(int argc, const char **argv, const char *prefix __used) status = run_perf_stat(argc, argv); } - print_stat(argc, argv); + if (status != -1) + print_stat(argc, argv); return status; } |