From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 532F7315D3B; Tue, 16 Dec 2025 06:23:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765866189; cv=none; b=deAW07IkYg1gZvLvtB+mGMxRShcyj7Sp4JPsKAkQMf48h5aPGBNLWvxpkVBOT9S9U3E8uDQ8ISU8wTEPak3Yj0P0a+jt2ieTnIXltHU5BcEYENkZ0bGEp2mrcYoYxeAd/d4IPOFpYutukZP8n77G+HhUeXFWwuawIxD70gEP+cQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765866189; c=relaxed/simple; bh=oJsHdVX4lcJ9KkJcLtmQuVzpM76327rCz7UiRhPoHT8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VzvkQGqAW7kOmIpEq1kEjMoidboYfCY65RZ3B5vGZcoYjvZiRLU9KhVNUjcYO/GwCxUHeGMIXVFajIszPZvPDw48JncZk64AqfFTOCg4tY9eYDykt9pD0nfNtRj3HBGMXX7mB5RQAZOohqVO6z+GbAavNLh/eKl5Nf3/zvuz1Eo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=c3AcD0WX; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="c3AcD0WX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C9A7BC4CEF1; Tue, 16 Dec 2025 06:23:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765866186; bh=oJsHdVX4lcJ9KkJcLtmQuVzpM76327rCz7UiRhPoHT8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=c3AcD0WXV6h6kAYL3/PC9/RLKJBla4qwgnADEgXFmwWdFf7Kn1vb5ajYfP22Up1wk 24tICJT/JUZwDVGPOHaJgJOKpT6+a0VYhCpFiMiRaHSSsew72MD0VK6LgDGvkhTKbO f/elEboLobvK99kRGtoGplWwzh6EK86rojeDYp1M6I+1+Q5Msq6Q5GRp+mmVOmv0v1 lwPvZ8nMovEp0M0o88GaH8nNpIHVDkItGVrUurn+E136aBy3s8fsyAkpByXsTYBUr5 J3K4CAsINhLdtdOdYRfowvC5sNmL8TThuDYK/4+3DkDqaGr8avLFnYv16twJodYUOs chYBrXTpx9D9Q== Date: Mon, 15 Dec 2025 22:23:04 -0800 From: Namhyung Kim To: James Clark Cc: Arnaldo Carvalho de Melo , Ian Rogers , Jiri Olsa , Adrian Hunter , Peter Zijlstra , Ingo Molnar , LKML , linux-perf-users@vger.kernel.org, Ankur Arora Subject: Re: [PATCH] perf bench: Add -t/--threads option to perf bench mem mmap Message-ID: References: <20251207085741.1388141-1-namhyung@kernel.org> <3c27128a-5cca-4c2f-a3f8-47b9a375bc7a@linaro.org> Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <3c27128a-5cca-4c2f-a3f8-47b9a375bc7a@linaro.org> Hi James, On Tue, Dec 09, 2025 at 01:01:25PM +0000, James Clark wrote: > > > On 07/12/2025 8:57 am, Namhyung Kim wrote: > > So that it can measure overhead of mmap_lock and/or per-VMA lock > > contention. > > > > $ perf bench mem mmap -f demand -l 1000 -t 1 > > # Running 'mem/mmap' benchmark: > > # function 'demand' (Demand loaded mmap()) > > # Copying 1MB bytes ... > > > > 2.914503 GB/sec > > > > $ perf bench mem mmap -f demand -l 1000 -t 2 > > # Running 'mem/mmap' benchmark: > > # function 'demand' (Demand loaded mmap()) > > # Copying 1MB bytes ... > > > > 888.769991 MB/sec > > > > $ perf bench mem mmap -f demand -l 1000 -t 3 > > # Running 'mem/mmap' benchmark: > > # function 'demand' (Demand loaded mmap()) > > # Copying 1MB bytes ... > > > > 757.658220 MB/sec > > > > $ perf bench mem mmap -f demand -l 1000 -t 4 > > # Running 'mem/mmap' benchmark: > > # function 'demand' (Demand loaded mmap()) > > # Copying 1MB bytes ... > > > > 316.410713 MB/sec > > Should this now say "MB/sec per thread" for nr_threads > 1? I think it could > be interpreted either way without a label, but I see you divided by > nr_threads in timeval2double(). Right, thanks for the review. I think we can add it unconditionally. Thanks, Namhyung > > > > > Cc: Ankur Arora > > Signed-off-by: Namhyung Kim > > --- > > tools/perf/Documentation/perf-bench.txt | 4 ++ > > tools/perf/bench/mem-functions.c | 74 +++++++++++++++++++++---- > > 2 files changed, 67 insertions(+), 11 deletions(-) > > > > diff --git a/tools/perf/Documentation/perf-bench.txt b/tools/perf/Documentation/perf-bench.txt > > index 1160224cb718392d..c5913cf59c988421 100644 > > --- a/tools/perf/Documentation/perf-bench.txt > > +++ b/tools/perf/Documentation/perf-bench.txt > > @@ -274,6 +274,10 @@ Repeat mmap() invocation this number of times. > > --cycles:: > > Use perf's cpu-cycles event instead of gettimeofday syscall. > > +-t:: > > +--threads=:: > > +Create multiple threads to call mmap/munmap concurrently. > > + > > SUITES FOR 'numa' > > ~~~~~~~~~~~~~~~~~ > > *mem*:: > > diff --git a/tools/perf/bench/mem-functions.c b/tools/perf/bench/mem-functions.c > > index 2908a3a796c932d0..e7e7d0b41fc7720f 100644 > > --- a/tools/perf/bench/mem-functions.c > > +++ b/tools/perf/bench/mem-functions.c > > @@ -26,6 +26,7 @@ > > #include > > #include > > #include > > +#include > > #define K 1024 > > @@ -41,6 +42,7 @@ static unsigned int nr_loops = 1; > > static bool use_cycles; > > static int cycles_fd; > > static unsigned int seed; > > +static unsigned int nr_threads = 1; > > static const struct option bench_common_options[] = { > > OPT_STRING('s', "size", &size_str, "1MB", > > @@ -174,7 +176,7 @@ static void clock_accum(union bench_clock *a, union bench_clock *b) > > static double timeval2double(struct timeval *ts) > > { > > - return (double)ts->tv_sec + (double)ts->tv_usec / (double)USEC_PER_SEC; > > + return (double)ts->tv_sec + (double)ts->tv_usec / (double)USEC_PER_SEC / nr_threads; > > } > > #define print_bps(x) do { \ > > @@ -494,16 +496,27 @@ static void mmap_page_touch(void *dst, size_t size, unsigned int page_shift, boo > > } > > } > > -static int do_mmap(const struct function *r, struct bench_params *p, > > - void *src __maybe_unused, void *dst __maybe_unused, > > - union bench_clock *accum) > > +struct mmap_data { > > + pthread_t id; > > + const struct function *func; > > + struct bench_params *params; > > + union bench_clock result; > > + unsigned int seed; > > + int error; > > +}; > > + > > +static void *do_mmap_thread(void *arg) > > { > > + struct mmap_data *data = arg; > > + const struct function *r = data->func; > > + struct bench_params *p = data->params; > > union bench_clock start, end, diff; > > mmap_op_t fn = r->fn.mmap_op; > > bool populate = strcmp(r->name, "populate") == 0; > > + void *dst; > > - if (p->seed) > > - srand(p->seed); > > + if (data->seed) > > + srand(data->seed); > > for (unsigned int i = 0; i < p->nr_loops; i++) { > > clock_get(&start); > > @@ -514,16 +527,53 @@ static int do_mmap(const struct function *r, struct bench_params *p, > > fn(dst, p->size, p->page_shift, p->seed); > > clock_get(&end); > > diff = clock_diff(&start, &end); > > - clock_accum(accum, &diff); > > + clock_accum(&data->result, &diff); > > bench_munmap(dst, p->size); > > } > > - return 0; > > + return data; > > out: > > - printf("# Memory allocation failed - maybe size (%s) %s?\n", size_str, > > - p->page_shift != PAGE_SHIFT_4KB ? "has insufficient hugepages" : "is too large"); > > - return -1; > > + data->error = -ENOMEM; > > + return NULL; > > +} > > + > > +static int do_mmap(const struct function *r, struct bench_params *p, > > + void *src __maybe_unused, void *dst __maybe_unused, > > + union bench_clock *accum) > > +{ > > + struct mmap_data *data; > > + int error = 0; > > + > > + data = calloc(nr_threads, sizeof(*data)); > > + if (!data) { > > + printf("# Failed to allocate thread resources\n"); > > + return -1; > > + } > > + > > + for (unsigned int i = 0; i < nr_threads; i++) { > > + data[i].func = r; > > + data[i].params = p; > > + if (p->seed) > > + data[i].seed = p->seed + i; > > + > > + if (pthread_create(&data[i].id, NULL, do_mmap_thread, &data[i]) < 0) > > + data[i].error = -errno; > > + } > > + > > + for (unsigned int i = 0; i < nr_threads; i++) { > > + pthread_join(data[i].id, NULL); > > + > > + clock_accum(accum, &data[i].result); > > + error |= data[i].error; > > + } > > + free(data); > > + > > + if (error) { > > + printf("# Memory allocation failed - maybe size (%s) %s?\n", size_str, > > + p->page_shift != PAGE_SHIFT_4KB ? "has insufficient hugepages" : "is too large"); > > + } > > + return error ? -1 : 0; > > } > > static const char * const bench_mem_mmap_usage[] = { > > @@ -548,6 +598,8 @@ int bench_mem_mmap(int argc, const char **argv) > > static const struct option bench_mmap_options[] = { > > OPT_UINTEGER('r', "randomize", &seed, > > "Seed to randomize page access offset."), > > + OPT_UINTEGER('t', "threads", &nr_threads, > > + "Number of threads to run concurrently (default: 1)."), > > OPT_PARENT(bench_common_options), > > OPT_END() > > }; >