From: Namhyung Kim Date: Thu, 19 Feb 2026 00:44:17 +0000 (-0800) Subject: perf bench: Add -t/--threads option to perf bench mem mmap X-Git-Tag: v7.1-rc1~91^2~127 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=c1f70c83be55e6721267f850dbfaf2ae07a04858;p=thirdparty%2Fkernel%2Flinux.git perf bench: Add -t/--threads option to perf bench mem mmap 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 ... 2.786858 GB/sec $ perf bench mem mmap -f demand -l 1000 -t 2 # Running 'mem/mmap' benchmark: # function 'demand' (Demand loaded mmap()) # Copying 1MB bytes ... 1.624468 GB/sec/thread ( +- 0.30% ) $ perf bench mem mmap -f demand -l 1000 -t 3 # Running 'mem/mmap' benchmark: # function 'demand' (Demand loaded mmap()) # Copying 1MB bytes ... 1.493068 GB/sec/thread ( +- 0.15% ) $ perf bench mem mmap -f demand -l 1000 -t 4 # Running 'mem/mmap' benchmark: # function 'demand' (Demand loaded mmap()) # Copying 1MB bytes ... 1.006087 GB/sec/thread ( +- 0.41% ) Reviewed-by: Ankur Arora Reviewed-by: James Clark Signed-off-by: Namhyung Kim --- diff --git a/tools/perf/Documentation/perf-bench.txt b/tools/perf/Documentation/perf-bench.txt index 1160224cb7183..c5913cf59c988 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 2908a3a796c93..f5ab41bb85bf6 100644 --- a/tools/perf/bench/mem-functions.c +++ b/tools/perf/bench/mem-functions.c @@ -7,13 +7,14 @@ * Written by Hitoshi Mitake */ -#include "debug.h" +#include "bench.h" #include "../perf-sys.h" #include -#include "../util/header.h" -#include "../util/cloexec.h" -#include "../util/string2.h" -#include "bench.h" +#include "util/cloexec.h" +#include "util/debug.h" +#include "util/header.h" +#include "util/stat.h" +#include "util/string2.h" #include "mem-memcpy-arch.h" #include "mem-memset-arch.h" @@ -26,6 +27,7 @@ #include #include #include +#include #define K 1024 @@ -41,6 +43,7 @@ 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", @@ -121,6 +124,8 @@ static struct perf_event_attr cycle_attr = { .config = PERF_COUNT_HW_CPU_CYCLES }; +static struct stats stats; + static int init_cycles(void) { cycles_fd = sys_perf_event_open(&cycle_attr, getpid(), -1, -1, perf_event_open_cloexec_flag()); @@ -174,18 +179,18 @@ 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 { \ if (x < K) \ - printf(" %14lf bytes/sec\n", x); \ + printf(" %14lf bytes/sec", x); \ else if (x < K * K) \ - printf(" %14lfd KB/sec\n", x / K); \ + printf(" %14lfd KB/sec", x / K); \ else if (x < K * K * K) \ - printf(" %14lf MB/sec\n", x / K / K); \ + printf(" %14lf MB/sec", x / K / K); \ else \ - printf(" %14lf GB/sec\n", x / K / K / K); \ + printf(" %14lf GB/sec", x / K / K / K); \ } while (0) static void __bench_mem_function(struct bench_mem_info *info, struct bench_params *p, @@ -196,6 +201,7 @@ static void __bench_mem_function(struct bench_mem_info *info, struct bench_param union bench_clock rt = { 0 }; void *src = NULL, *dst = NULL; + init_stats(&stats); printf("# function '%s' (%s)\n", r->name, r->desc); if (r->fn.init && r->fn.init(info, p, &src, &dst)) @@ -210,11 +216,16 @@ static void __bench_mem_function(struct bench_mem_info *info, struct bench_param switch (bench_format) { case BENCH_FORMAT_DEFAULT: if (use_cycles) { - printf(" %14lf cycles/byte\n", (double)rt.cycles/(double)p->size_total); + printf(" %14lf cycles/byte", (double)rt.cycles/(double)p->size_total); } else { result_bps = (double)p->size_total/timeval2double(&rt.tv); print_bps(result_bps); } + if (nr_threads > 1) { + printf("/thread\t( +- %6.2f%% )", + rel_stddev_stats(stddev_stats(&stats), avg_stats(&stats))); + } + printf("\n"); break; case BENCH_FORMAT_SIMPLE: @@ -494,16 +505,27 @@ 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 +536,59 @@ 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++) { + union bench_clock *t = &data[i].result; + + pthread_join(data[i].id, NULL); + + clock_accum(accum, t); + if (use_cycles) + update_stats(&stats, t->cycles); + else + update_stats(&stats, t->tv.tv_sec * 1e6 + t->tv.tv_usec); + 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 +613,8 @@ 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() };