From: Steven Rostedt 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 --- kernel/trace/ring_buffer_benchmark.c | 11 +++++++++-- 1 files changed, 9 insertions(+), 2 deletions(-) diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c index f4ceb45..a7c048b 100644 --- a/kernel/trace/ring_buffer_benchmark.c +++ b/kernel/trace/ring_buffer_benchmark.c @@ -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"); -- 1.6.2.4 -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/