remarkable-linux/tools
Stephane Eranian 6b1bee9035 perf tools: fix broken perf record -a mode
The following commit:
b52956c perf tools: Allow multiple threads or processes in record, stat, top

introduced a bug in the thread_map code which caused perf record -a to
not setup system-wide monitoring properly.

$ taskset -c 1 noploop 1000 &
$ perf record -a -C 1 sleep 10
$ perf report -D | tail -20
cycles stats:
           TOTAL events:       4413
            MMAP events:       4025
            COMM events:        340
          SAMPLE events:         48

Here I was expecting about 10,000 samples and not 48.

In system-wide mode, the PID passed to perf_event_open() must be -1 and
it was 0. That caused the kernel to setup a per-process event on PID:0.
Consequently, the number of samples captured does not correspond to the
requested measurement.

The following one-liner fixes the problem for me with or without -C.

I would also suggest to change the malloc() to something that matches
the struct definition. thread_map->map[] is declared as int map[] and
not pid_t map[]. If map[] can only contain pids, then change the struct
definition.

Acked-by: David Ahern <dsahern@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120221145424.GA6757@quad
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-02-21 15:05:43 -02:00
..
firewire
hv Staging: hv: move hyperv code out of staging directory 2011-10-10 22:52:55 -06:00
lguest lguest: move the lguest tool to the tools directory 2012-01-12 15:44:47 +10:30
nfsd NFSD: Added fault injection script 2011-11-07 21:10:47 -05:00
perf perf tools: fix broken perf record -a mode 2012-02-21 15:05:43 -02:00
power Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/lenb/linux 2012-01-18 15:51:48 -08:00
slub Merge branches 'slab/next' and 'slub/partial' into slab/for-linus 2011-10-26 18:09:12 +03:00
testing Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-ktest 2012-01-16 17:53:27 -08:00
usb
virtio virtio: rename virtqueue_add_buf_gfp to virtqueue_add_buf 2012-01-12 15:44:42 +10:30