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ring-buffer: only periodically call cond_resched to ring-buffer-benchmark

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Calling cond_resched at every iteration of the loop adds a bit of
overhead to the benchmark.

This patch does two things.

1) only calls cond-resched when CONFIG_PREEMPT is not enabled
2) only calls cond-resched after so many traces has been performed.

[ Impact: less overhead to the ring-buffer-benchmark ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2009-05-07 14:20:28 -04:00 committed by Steven Rostedt
parent 65b7724204
commit 0574ea421b
1 changed files with 9 additions and 2 deletions
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11
kernel/trace/ring_buffer_benchmark.c
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@ -218,16 +218,23 @@ static void ring_buffer_producer(void)
}
do_gettimeofday(&end_tv);
if (consumer && !(++cnt % wakeup_interval))
cnt++;
if (consumer && !(cnt % wakeup_interval))
wake_up_process(consumer);
#ifndef CONFIG_PREEMPT
/*
* If we are a non preempt kernel, the 10 second run will
* stop everything while it runs. Instead, we will call
* cond_resched and also add any time that was lost by a
* rescedule.
*
* Do a cond resched at the same frequency we would wake up
* the reader.
*/
cond_resched();
if (cnt % wakeup_interval)
cond_resched();
#endif
} while (end_tv.tv_sec < (start_tv.tv_sec + RUN_TIME) && !kill_test);
pr_info("End ring buffer hammer\n");