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 <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Eric Dumazet <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/20120221145424.GA6757@quad
Signed-off-by: Stephane Eranian <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Allow a user to collect events for multiple threads or processes
using a comma separated list.
e.g., collect data on a VM and its vhost thread:
perf top -p 21483,21485
perf stat -p 21483,21485 -ddd
perf record -p 21483,21485
or monitoring vcpu threads
perf top -t 21488,21489
perf stat -t 21488,21489 -ddd
perf record -t 21488,21489
Cc: Frederic Weisbecker <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: David Ahern <[email protected]>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
To untangle it from struct thread handling, that is tied to symbols, etc.
Right now in the python bindings I'm working on I need just a subset of
the util/ files, untangling it allows me to do that.
Cc: Frederic Weisbecker <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Tom Zanussi <[email protected]>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Arnaldo Carvalho de Melo