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Date: Wed, 1 Oct 2014 16:50:39 -0300 From: Arnaldo Carvalho de Melo <acme@...nel.org> To: Ingo Molnar <mingo@...nel.org> Cc: linux-kernel@...r.kernel.org, Davidlohr Bueso <dave@...olabs.net>, Davidlohr Bueso <dbueso@...e.de>, Arnaldo Carvalho de Melo <acme@...hat.com> Subject: [PATCH 4/8] perf bench futex: Sanitize -q option in requeue From: Davidlohr Bueso <dave@...olabs.net> When given the number of threads to requeue at once by user input, there's always the risk of this value being larger than the total number of threads. This doesn't make any sense, and the kernel can easily deal with such sort of situations, hence no big deal. We should however prevent bogus output such as: ./perf bench --repeat 2 futex requeue -q 10 Run summary [PID 22210]: Requeuing 4 threads (from [private] 0x99ef3c to 0x99ef38), 10 at a time. [Run 1]: Requeued 10 of 4 threads in 0.0040 ms [Run 2]: Requeued 10 of 4 threads in 0.0030 ms Requeued 10 of 4 threads in 0.0035 ms (+-14.29%) Signed-off-by: Davidlohr Bueso <dbueso@...e.de> Cc: Davidlohr Bueso <dbueso@...e.de> Link: http://lkml.kernel.org/r/1412008868-22328-2-git-send-email-dave@stgolabs.net Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com> --- tools/perf/bench/futex-requeue.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/perf/bench/futex-requeue.c b/tools/perf/bench/futex-requeue.c index 9837a8831406..bedff6b5b3cf 100644 --- a/tools/perf/bench/futex-requeue.c +++ b/tools/perf/bench/futex-requeue.c @@ -172,6 +172,9 @@ int bench_futex_requeue(int argc, const char **argv, gettimeofday(&end, NULL); timersub(&end, &start, &runtime); + if (nrequeued > nthreads) + nrequeued = nthreads; + update_stats(&requeued_stats, nrequeued); update_stats(&requeuetime_stats, runtime.tv_usec); @@ -190,7 +193,6 @@ int bench_futex_requeue(int argc, const char **argv, if (ret) err(EXIT_FAILURE, "pthread_join"); } - } /* cleanup & report results */ -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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