perf_events: Improve task_sched_in()
authoreranian@google.com <eranian@google.com>
Thu, 11 Mar 2010 06:26:05 +0000 (22:26 -0800)
committerIngo Molnar <mingo@elte.hu>
Thu, 11 Mar 2010 14:23:28 +0000 (15:23 +0100)
commit9b33fa6ba0e2f90fdf407501db801c2511121564
treef5314e450afae1f1d4a9feadb0693e20584f62a6
parentcaa0142d84ceb0fc83e28f0475d0a7316cb6df77
perf_events: Improve task_sched_in()

This patch is an optimization in perf_event_task_sched_in() to avoid
scheduling the events twice in a row.

Without it, the perf_disable()/perf_enable() pair is invoked twice,
thereby pinned events counts while scheduling flexible events and we go
throuh hw_perf_enable() twice.

By encapsulating, the whole sequence into perf_disable()/perf_enable() we
ensure, hw_perf_enable() is going to be invoked only once because of the
refcount protection.

Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1268288765-5326-1-git-send-email-eranian@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
kernel/perf_event.c