| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <3c27128a-5cca-4c2f-a3f8-47b9a375bc7a@linaro.org>
Date: Tue, 9 Dec 2025 13:01:25 +0000
From: James Clark <james.clark@...aro.org>
To: Namhyung Kim <namhyung@...nel.org>,
Arnaldo Carvalho de Melo <acme@...nel.org>, Ian Rogers <irogers@...gle.com>
Cc: Jiri Olsa <jolsa@...nel.org>, Adrian Hunter <adrian.hunter@...el.com>,
Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...nel.org>,
LKML <linux-kernel@...r.kernel.org>, linux-perf-users@...r.kernel.org,
Ankur Arora <ankur.a.arora@...cle.com>
Subject: Re: [PATCH] perf bench: Add -t/--threads option to perf bench mem
mmap
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().
>
> Cc: Ankur Arora <ankur.a.arora@...cle.com>
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> ---
> 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=<NUM>::
> +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 <errno.h>
> #include <linux/time64.h>
> #include <linux/log2.h>
> +#include <pthread.h>
>
> #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()
> };
Powered by blists - more mailing lists