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perf bench: Add -t/--threads option to perf bench mem mmap

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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 <ankur.a.arora@oracle.com>
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
This commit is contained in:
Namhyung Kim 2026-02-18 16:44:17 -08:00
parent af894feb32
commit c1f70c83be
2 changed files with 92 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
tools/perf/Documentation/perf-bench.txt
View File

@ -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*::

109
tools/perf/bench/mem-functions.c
View File

@ -7,13 +7,14 @@
* Written by Hitoshi Mitake <mitake@dcl.info.waseda.ac.jp>
*/
#include "debug.h"
#include "bench.h"
#include "../perf-sys.h"
#include <subcmd/parse-options.h>
#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 <errno.h>
#include <linux/time64.h>
#include <linux/log2.h>
#include <pthread.h>
#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()
};