Commit 231457ec authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Arnaldo Carvalho de Melo

perf bench: Add epoll_ctl(2) benchmark

Benchmark the various operations allowed for epoll_ctl(2).  The idea is
to concurrently stress a single epoll instance doing add/mod/del
operations.

Committer testing:

  # perf bench epoll ctl
  # Running 'epoll/ctl' benchmark:
  Run summary [PID 20344]: 4 threads doing epoll_ctl ops 64 file-descriptors for 8 secs.

  [thread  0] fdmap: 0x21a46b0 ... 0x21a47ac [ add: 1680960 ops; mod: 1680960 ops; del: 1680960 ops ]
  [thread  1] fdmap: 0x21a4960 ... 0x21a4a5c [ add: 1685440 ops; mod: 1685440 ops; del: 1685440 ops ]
  [thread  2] fdmap: 0x21a4c10 ... 0x21a4d0c [ add: 1674368 ops; mod: 1674368 ops; del: 1674368 ops ]
  [thread  3] fdmap: 0x21a4ec0 ... 0x21a4fbc [ add: 1677568 ops; mod: 1677568 ops; del: 1677568 ops ]

  Averaged 1679584 ADD operations (+- 0.14%)
  Averaged 1679584 MOD operations (+- 0.14%)
  Averaged 1679584 DEL operations (+- 0.14%)
  #

Lets measure those calls with 'perf trace' to get a glympse at what this
benchmark is doing in terms of syscalls:

  # perf trace -m32768 -s perf bench epoll ctl
  # Running 'epoll/ctl' benchmark:
  Run summary [PID 20405]: 4 threads doing epoll_ctl ops 64 file-descriptors for 8 secs.

  [thread  0] fdmap: 0x21764e0 ... 0x21765dc [ add: 1100480 ops; mod: 1100480 ops; del: 1100480 ops ]
  [thread  1] fdmap: 0x2176790 ... 0x217688c [ add: 1250176 ops; mod: 1250176 ops; del: 1250176 ops ]
  [thread  2] fdmap: 0x2176a40 ... 0x2176b3c [ add: 1022464 ops; mod: 1022464 ops; del: 1022464 ops ]
  [thread  3] fdmap: 0x2176cf0 ... 0x2176dec [ add: 705472 ops; mod: 705472 ops; del: 705472 ops ]

  Averaged 1019648 ADD operations (+- 11.27%)
  Averaged 1019648 MOD operations (+- 11.27%)
  Averaged 1019648 DEL operations (+- 11.27%)

  Summary of events:

  epoll-ctl (20405), 1264 events, 0.0%

   syscall            calls    total       min       avg       max      stddev
                               (msec)    (msec)    (msec)    (msec)        (%)
   --------------- -------- --------- --------- --------- ---------     ------
   eventfd2             256     9.514     0.001     0.037     5.243     68.00%
   clone                  4     1.245     0.204     0.311     0.531     24.13%
   mprotect              66     0.345     0.002     0.005     0.021      7.43%
   openat                45     0.313     0.004     0.007     0.073     21.93%
   mmap                  88     0.302     0.002     0.003     0.013      5.02%
   futex                  4     0.160     0.002     0.040     0.140     83.43%
   sched_setaffinity      4     0.124     0.005     0.031     0.070     49.39%
   read                  44     0.103     0.001     0.002     0.013     15.54%
   fstat                 40     0.052     0.001     0.001     0.003      5.43%
   close                 39     0.039     0.001     0.001     0.001      1.48%
   stat                   9     0.034     0.003     0.004     0.006      7.30%
   access                 3     0.023     0.007     0.008     0.008      4.25%
   open                   2     0.021     0.008     0.011     0.013     22.60%
   getdents               4     0.019     0.001     0.005     0.009     37.15%
   write                  2     0.013     0.004     0.007     0.009     38.48%
   munmap                 1     0.010     0.010     0.010     0.010      0.00%
   brk                    3     0.006     0.001     0.002     0.003     26.34%
   rt_sigprocmask         2     0.004     0.001     0.002     0.003     43.95%
   rt_sigaction           3     0.004     0.001     0.001     0.002     16.07%
   prlimit64              3     0.004     0.001     0.001     0.001      5.39%
   prctl                  1     0.003     0.003     0.003     0.003      0.00%
   epoll_create           1     0.003     0.003     0.003     0.003      0.00%
   lseek                  2     0.002     0.001     0.001     0.001     11.42%
   sched_getaffinity        1     0.002     0.002     0.002     0.002      0.00%
   arch_prctl             1     0.002     0.002     0.002     0.002      0.00%
   set_tid_address        1     0.001     0.001     0.001     0.001      0.00%
   getpid                 1     0.001     0.001     0.001     0.001      0.00%
   set_robust_list        1     0.001     0.001     0.001     0.001      0.00%
   execve                 1     0.000     0.000     0.000     0.000      0.00%

 epoll-ctl (20406), 1245480 events, 14.6%

   syscall            calls    total       min       avg       max      stddev
                               (msec)    (msec)    (msec)    (msec)        (%)
   --------------- -------- --------- --------- --------- ---------     ------
   epoll_ctl         619511  1034.927     0.001     0.002     6.691      0.67%
   nanosleep           3226   616.114     0.006     0.191    10.376      7.57%
   futex                  2    11.336     0.002     5.668    11.334     99.97%
   set_robust_list        1     0.001     0.001     0.001     0.001      0.00%
   clone                  1     0.000     0.000     0.000     0.000      0.00%

 epoll-ctl (20407), 1243151 events, 14.5%

   syscall            calls    total       min       avg       max      stddev
                               (msec)    (msec)    (msec)    (msec)        (%)
   --------------- -------- --------- --------- --------- ---------     ------
   epoll_ctl         618350  1042.181     0.001     0.002     2.512      0.40%
   nanosleep           3220   366.261     0.012     0.114    18.162      9.59%
   futex                  4     5.463     0.001     1.366     5.427     99.12%
   set_robust_list        1     0.002     0.002     0.002     0.002      0.00%

 epoll-ctl (20408), 1801690 events, 21.1%

   syscall            calls    total       min       avg       max      stddev
                               (msec)    (msec)    (msec)    (msec)        (%)
   --------------- -------- --------- --------- --------- ---------     ------
   epoll_ctl         896174  1540.581     0.001     0.002     6.987      0.74%
   nanosleep           4667   783.393     0.006     0.168    10.419      7.10%
   futex                  2     4.682     0.002     2.341     4.681     99.93%
   set_robust_list        1     0.002     0.002     0.002     0.002      0.00%
   clone                  1     0.000     0.000     0.000     0.000      0.00%

 epoll-ctl (20409), 4254890 events, 49.8%

   syscall            calls    total       min       avg       max      stddev
                               (msec)    (msec)    (msec)    (msec)        (%)
   --------------- -------- --------- --------- --------- ---------     ------
   epoll_ctl        2116416  3768.097     0.001     0.002     9.956      0.41%
   nanosleep          11023  1141.778     0.006     0.104     9.447      4.95%
   futex                  3     0.037     0.002     0.012     0.029     70.50%
   set_robust_list        1     0.008     0.008     0.008     0.008      0.00%
   madvise                1     0.005     0.005     0.005     0.005      0.00%
   clone                  1     0.000     0.000     0.000     0.000      0.00%
  #

Committer notes:

Fix build on fedora:24-x-ARC-uClibc, debian:experimental-x-mips,
debian:experimental-x-mipsel, ubuntu:16.04-x-arm and ubuntu:16.04-x-powerpc

    CC       /tmp/build/perf/bench/epoll-ctl.o
  bench/epoll-ctl.c: In function 'init_fdmaps':
  bench/epoll-ctl.c:214:16: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
    for (i = 0; i < nfds; i+=inc) {
                  ^
  bench/epoll-ctl.c: In function 'bench_epoll_ctl':
  bench/epoll-ctl.c:377:16: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
    for (i = 0; i < nthreads; i++) {
                  ^
  bench/epoll-ctl.c:388:16: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare]
    for (i = 0; i < nthreads; i++) {
                  ^
  cc1: all warnings being treated as errors
Signed-off-by: default avatarDavidlohr Bueso <dbueso@suse.de>
Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Jason Baron <jbaron@akamai.com>
Link: http://lkml.kernel.org/r/20181106152226.20883-3-dave@stgolabs.net
[ Use inttypes.h to print rlim_t fields, fixing the build on Alpine Linux / musl libc ]
[ Check if eventfd() is available, i.e. if HAVE_EVENTFD is defined ]
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 121dd9ea
......@@ -211,6 +211,9 @@ SUITES FOR 'epoll'
*wait*::
Suite for evaluating concurrent epoll_wait calls.
*ctl*::
Suite for evaluating multiple epoll_ctl calls.
SEE ALSO
--------
linkperf:perf[1]
......@@ -8,6 +8,7 @@ perf-y += futex-requeue.o
perf-y += futex-lock-pi.o
perf-y += epoll-wait.o
perf-y += epoll-ctl.o
perf-$(CONFIG_X86_64) += mem-memcpy-x86-64-lib.o
perf-$(CONFIG_X86_64) += mem-memcpy-x86-64-asm.o
......
......@@ -39,6 +39,7 @@ int bench_futex_requeue(int argc, const char **argv);
int bench_futex_lock_pi(int argc, const char **argv);
int bench_epoll_wait(int argc, const char **argv);
int bench_epoll_ctl(int argc, const char **argv);
#define BENCH_FORMAT_DEFAULT_STR "default"
#define BENCH_FORMAT_DEFAULT 0
......
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2018 Davidlohr Bueso.
*
* Benchmark the various operations allowed for epoll_ctl(2).
* The idea is to concurrently stress a single epoll instance
*/
#ifdef HAVE_EVENTFD
/* For the CLR_() macros */
#include <string.h>
#include <pthread.h>
#include <errno.h>
#include <inttypes.h>
#include <signal.h>
#include <stdlib.h>
#include <linux/compiler.h>
#include <linux/kernel.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <sys/epoll.h>
#include <sys/eventfd.h>
#include "../util/stat.h"
#include <subcmd/parse-options.h>
#include "bench.h"
#include "cpumap.h"
#include <err.h>
#define printinfo(fmt, arg...) \
do { if (__verbose) printf(fmt, ## arg); } while (0)
static unsigned int nthreads = 0;
static unsigned int nsecs = 8;
struct timeval start, end, runtime;
static bool done, __verbose, randomize;
/*
* epoll related shared variables.
*/
/* Maximum number of nesting allowed inside epoll sets */
#define EPOLL_MAXNESTS 4
enum {
OP_EPOLL_ADD,
OP_EPOLL_MOD,
OP_EPOLL_DEL,
EPOLL_NR_OPS,
};
static int epollfd;
static int *epollfdp;
static bool noaffinity;
static unsigned int nested = 0;
/* amount of fds to monitor, per thread */
static unsigned int nfds = 64;
static pthread_mutex_t thread_lock;
static unsigned int threads_starting;
static struct stats all_stats[EPOLL_NR_OPS];
static pthread_cond_t thread_parent, thread_worker;
struct worker {
int tid;
pthread_t thread;
unsigned long ops[EPOLL_NR_OPS];
int *fdmap;
};
static const struct option options[] = {
OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"),
OPT_UINTEGER('r', "runtime", &nsecs, "Specify runtime (in seconds)"),
OPT_UINTEGER('f', "nfds", &nfds, "Specify amount of file descriptors to monitor for each thread"),
OPT_BOOLEAN( 'n', "noaffinity", &noaffinity, "Disables CPU affinity"),
OPT_UINTEGER( 'N', "nested", &nested, "Nesting level epoll hierarchy (default is 0, no nesting)"),
OPT_BOOLEAN( 'R', "randomize", &randomize, "Perform random operations on random fds"),
OPT_BOOLEAN( 'v', "verbose", &__verbose, "Verbose mode"),
OPT_END()
};
static const char * const bench_epoll_ctl_usage[] = {
"perf bench epoll ctl <options>",
NULL
};
static void toggle_done(int sig __maybe_unused,
siginfo_t *info __maybe_unused,
void *uc __maybe_unused)
{
/* inform all threads that we're done for the day */
done = true;
gettimeofday(&end, NULL);
timersub(&end, &start, &runtime);
}
static void nest_epollfd(void)
{
unsigned int i;
struct epoll_event ev;
if (nested > EPOLL_MAXNESTS)
nested = EPOLL_MAXNESTS;
printinfo("Nesting level(s): %d\n", nested);
epollfdp = calloc(nested, sizeof(int));
if (!epollfd)
err(EXIT_FAILURE, "calloc");
for (i = 0; i < nested; i++) {
epollfdp[i] = epoll_create(1);
if (epollfd < 0)
err(EXIT_FAILURE, "epoll_create");
}
ev.events = EPOLLHUP; /* anything */
ev.data.u64 = i; /* any number */
for (i = nested - 1; i; i--) {
if (epoll_ctl(epollfdp[i - 1], EPOLL_CTL_ADD,
epollfdp[i], &ev) < 0)
err(EXIT_FAILURE, "epoll_ctl");
}
if (epoll_ctl(epollfd, EPOLL_CTL_ADD, *epollfdp, &ev) < 0)
err(EXIT_FAILURE, "epoll_ctl");
}
static inline void do_epoll_op(struct worker *w, int op, int fd)
{
int error;
struct epoll_event ev;
ev.events = EPOLLIN;
ev.data.u64 = fd;
switch (op) {
case OP_EPOLL_ADD:
error = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev);
break;
case OP_EPOLL_MOD:
ev.events = EPOLLOUT;
error = epoll_ctl(epollfd, EPOLL_CTL_MOD, fd, &ev);
break;
case OP_EPOLL_DEL:
error = epoll_ctl(epollfd, EPOLL_CTL_DEL, fd, NULL);
break;
default:
error = 1;
break;
}
if (!error)
w->ops[op]++;
}
static inline void do_random_epoll_op(struct worker *w)
{
unsigned long rnd1 = random(), rnd2 = random();
int op, fd;
fd = w->fdmap[rnd1 % nfds];
op = rnd2 % EPOLL_NR_OPS;
do_epoll_op(w, op, fd);
}
static void *workerfn(void *arg)
{
unsigned int i;
struct worker *w = (struct worker *) arg;
struct timespec ts = { .tv_sec = 0,
.tv_nsec = 250 };
pthread_mutex_lock(&thread_lock);
threads_starting--;
if (!threads_starting)
pthread_cond_signal(&thread_parent);
pthread_cond_wait(&thread_worker, &thread_lock);
pthread_mutex_unlock(&thread_lock);
/* Let 'em loose */
do {
/* random */
if (randomize) {
do_random_epoll_op(w);
} else {
for (i = 0; i < nfds; i++) {
do_epoll_op(w, OP_EPOLL_ADD, w->fdmap[i]);
do_epoll_op(w, OP_EPOLL_MOD, w->fdmap[i]);
do_epoll_op(w, OP_EPOLL_DEL, w->fdmap[i]);
}
}
nanosleep(&ts, NULL);
} while (!done);
return NULL;
}
static void init_fdmaps(struct worker *w, int pct)
{
unsigned int i;
int inc;
struct epoll_event ev;
if (!pct)
return;
inc = 100/pct;
for (i = 0; i < nfds; i+=inc) {
ev.data.fd = w->fdmap[i];
ev.events = EPOLLIN;
if (epoll_ctl(epollfd, EPOLL_CTL_ADD, w->fdmap[i], &ev) < 0)
err(EXIT_FAILURE, "epoll_ct");
}
}
static int do_threads(struct worker *worker, struct cpu_map *cpu)
{
pthread_attr_t thread_attr, *attrp = NULL;
cpu_set_t cpuset;
unsigned int i, j;
int ret;
if (!noaffinity)
pthread_attr_init(&thread_attr);
for (i = 0; i < nthreads; i++) {
struct worker *w = &worker[i];
w->tid = i;
w->fdmap = calloc(nfds, sizeof(int));
if (!w->fdmap)
return 1;
for (j = 0; j < nfds; j++) {
w->fdmap[j] = eventfd(0, EFD_NONBLOCK);
if (w->fdmap[j] < 0)
err(EXIT_FAILURE, "eventfd");
}
/*
* Lets add 50% of the fdmap to the epoll instance, and
* do it before any threads are started; otherwise there is
* an initial bias of the call failing (mod and del ops).
*/
if (randomize)
init_fdmaps(w, 50);
if (!noaffinity) {
CPU_ZERO(&cpuset);
CPU_SET(cpu->map[i % cpu->nr], &cpuset);
ret = pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset);
if (ret)
err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
attrp = &thread_attr;
}
ret = pthread_create(&w->thread, attrp, workerfn,
(void *)(struct worker *) w);
if (ret)
err(EXIT_FAILURE, "pthread_create");
}
if (!noaffinity)
pthread_attr_destroy(&thread_attr);
return ret;
}
static void print_summary(void)
{
int i;
unsigned long avg[EPOLL_NR_OPS];
double stddev[EPOLL_NR_OPS];
for (i = 0; i < EPOLL_NR_OPS; i++) {
avg[i] = avg_stats(&all_stats[i]);
stddev[i] = stddev_stats(&all_stats[i]);
}
printf("\nAveraged %ld ADD operations (+- %.2f%%)\n",
avg[OP_EPOLL_ADD], rel_stddev_stats(stddev[OP_EPOLL_ADD],
avg[OP_EPOLL_ADD]));
printf("Averaged %ld MOD operations (+- %.2f%%)\n",
avg[OP_EPOLL_MOD], rel_stddev_stats(stddev[OP_EPOLL_MOD],
avg[OP_EPOLL_MOD]));
printf("Averaged %ld DEL operations (+- %.2f%%)\n",
avg[OP_EPOLL_DEL], rel_stddev_stats(stddev[OP_EPOLL_DEL],
avg[OP_EPOLL_DEL]));
}
int bench_epoll_ctl(int argc, const char **argv)
{
int j, ret = 0;
struct sigaction act;
struct worker *worker = NULL;
struct cpu_map *cpu;
struct rlimit rl, prevrl;
unsigned int i;
argc = parse_options(argc, argv, options, bench_epoll_ctl_usage, 0);
if (argc) {
usage_with_options(bench_epoll_ctl_usage, options);
exit(EXIT_FAILURE);
}
sigfillset(&act.sa_mask);
act.sa_sigaction = toggle_done;
sigaction(SIGINT, &act, NULL);
cpu = cpu_map__new(NULL);
if (!cpu)
goto errmem;
/* a single, main epoll instance */
epollfd = epoll_create(1);
if (epollfd < 0)
err(EXIT_FAILURE, "epoll_create");
/*
* Deal with nested epolls, if any.
*/
if (nested)
nest_epollfd();
/* default to the number of CPUs */
if (!nthreads)
nthreads = cpu->nr;
worker = calloc(nthreads, sizeof(*worker));
if (!worker)
goto errmem;
if (getrlimit(RLIMIT_NOFILE, &prevrl))
err(EXIT_FAILURE, "getrlimit");
rl.rlim_cur = rl.rlim_max = nfds * nthreads * 2 + 50;
printinfo("Setting RLIMIT_NOFILE rlimit from %" PRIu64 " to: %" PRIu64 "\n",
(uint64_t)prevrl.rlim_max, (uint64_t)rl.rlim_max);
if (setrlimit(RLIMIT_NOFILE, &rl) < 0)
err(EXIT_FAILURE, "setrlimit");
printf("Run summary [PID %d]: %d threads doing epoll_ctl ops "
"%d file-descriptors for %d secs.\n\n",
getpid(), nthreads, nfds, nsecs);
for (i = 0; i < EPOLL_NR_OPS; i++)
init_stats(&all_stats[i]);
pthread_mutex_init(&thread_lock, NULL);
pthread_cond_init(&thread_parent, NULL);
pthread_cond_init(&thread_worker, NULL);
threads_starting = nthreads;
gettimeofday(&start, NULL);
do_threads(worker, cpu);
pthread_mutex_lock(&thread_lock);
while (threads_starting)
pthread_cond_wait(&thread_parent, &thread_lock);
pthread_cond_broadcast(&thread_worker);
pthread_mutex_unlock(&thread_lock);
sleep(nsecs);
toggle_done(0, NULL, NULL);
printinfo("main thread: toggling done\n");
for (i = 0; i < nthreads; i++) {
ret = pthread_join(worker[i].thread, NULL);
if (ret)
err(EXIT_FAILURE, "pthread_join");
}
/* cleanup & report results */
pthread_cond_destroy(&thread_parent);
pthread_cond_destroy(&thread_worker);
pthread_mutex_destroy(&thread_lock);
for (i = 0; i < nthreads; i++) {
unsigned long t[EPOLL_NR_OPS];
for (j = 0; j < EPOLL_NR_OPS; j++) {
t[j] = worker[i].ops[j];
update_stats(&all_stats[j], t[j]);
}
if (nfds == 1)
printf("[thread %2d] fdmap: %p [ add: %04ld; mod: %04ld; del: %04lds ops ]\n",
worker[i].tid, &worker[i].fdmap[0],
t[OP_EPOLL_ADD], t[OP_EPOLL_MOD], t[OP_EPOLL_DEL]);
else
printf("[thread %2d] fdmap: %p ... %p [ add: %04ld ops; mod: %04ld ops; del: %04ld ops ]\n",
worker[i].tid, &worker[i].fdmap[0],
&worker[i].fdmap[nfds-1],
t[OP_EPOLL_ADD], t[OP_EPOLL_MOD], t[OP_EPOLL_DEL]);
}
print_summary();
close(epollfd);
return ret;
errmem:
err(EXIT_FAILURE, "calloc");
}
#endif // HAVE_EVENTFD
......@@ -71,6 +71,7 @@ static struct bench futex_benchmarks[] = {
#ifdef HAVE_EVENTFD
static struct bench epoll_benchmarks[] = {
{ "wait", "Benchmark epoll concurrent epoll_waits", bench_epoll_wait },
{ "ctl", "Benchmark epoll concurrent epoll_ctls", bench_epoll_ctl },
{ "all", "Run all futex benchmarks", NULL },
{ NULL, NULL, NULL }
};
......
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