perf_counter: optimize perf_counter_task_tick()
authorPeter Zijlstra <a.p.zijlstra@chello.nl>
Fri, 8 May 2009 16:52:21 +0000 (18:52 +0200)
committerIngo Molnar <mingo@elte.hu>
Fri, 8 May 2009 18:36:57 +0000 (20:36 +0200)
commit7fc23a5380797012e92a9633169440f2f4a21253
treeb136302efccd407ef4ee608de40042bedd0ab660
parent3611dfb8eda847c1c8e1a052f57206f7fddc6a7c
perf_counter: optimize perf_counter_task_tick()

perf_counter_task_tick() does way too much work to find out
there's nothing to do. Provide an easy short-circuit for the
normal case where there are no counters on the system.

[ Impact: micro-optimization ]

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
LKML-Reference: <20090508170028.750619201@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
kernel/perf_counter.c