cosmopolitan/test/libc/intrin/lockscale_test.c
Justine Tunney f7ff77d865
Make fixes and improvements
- Invent iso8601us() for faster timestamps
- Improve --strace descriptions of sigset_t
- Rebuild the Landlock Make bootstrap binary
- Introduce MODE=sysv for non-Windows builds
- Permit OFD fcntl() locks under pledge(flock)
- redbean can now protect your kernel from ddos
- Have vfork() fallback to sys_fork() not fork()
- Change kmalloc() to not die when out of memory
- Improve documentation for some termios functions
- Rewrite putenv() and friends to conform to POSIX
- Fix linenoise + strace verbosity issue on Windows
- Fix regressions in our ability to show backtraces
- Change redbean SetHeader() to no-op if value is nil
- Improve fcntl() so SQLite locks work in non-WAL mode
- Remove some unnecessary work during fork() on Windows
- Create redbean-based SSL reverse proxy for IPv4 TurfWar
- Fix ape/apeinstall.sh warning when using non-bash shells
- Add ProgramTrustedIp(), and IsTrustedIp() APIs to redbean
- Support $PWD, $UID, $GID, and $EUID in command interpreter
- Introduce experimental JTqFpD APE prefix for non-Windows builds
- Invent blackhole daemon for firewalling IP addresses via UNIX named socket
- Add ProgramTokenBucket(), AcquireToken(), and CountTokens() APIs to redbean
2022-10-19 07:19:19 -07:00

86 lines
3.5 KiB
C

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/atomic.h"
#include "libc/calls/calls.h"
#include "libc/calls/struct/timespec.h"
#include "libc/mem/gc.h"
#include "libc/mem/mem.h"
#include "libc/stdio/stdio.h"
#include "libc/testlib/testlib.h"
#include "libc/thread/thread.h"
#include "libc/time/time.h"
/**
* @fileoverview Lock Waiter Scalability Test
*
* This test can be run as follows:
*
* make o//test/libc/intrin/lockscale_test.com.runs V=5 TESTARGS=-b
*
* It's intended to demonstrate the importance of futexes. On systems
* that don't have them, this test consumes orders of a magnitude more
* cpu time, because there's a lot of waiters and they need to wait a
* very long time.
*/
#define WAITERS 100
#define ITERATIONS 10000
atomic_int x;
pthread_t t[WAITERS];
pthread_mutex_t lock;
pthread_barrier_t barrier;
void Worker(void) {
pthread_mutex_lock(&lock);
pthread_barrier_wait(&barrier);
for (x = 0; x < ITERATIONS; ++x) {
sched_yield();
}
pthread_mutex_unlock(&lock);
}
void *Waiter(void *arg) {
pthread_barrier_wait(&barrier);
pthread_mutex_lock(&lock);
ASSERT_EQ(ITERATIONS, x);
pthread_mutex_unlock(&lock);
return 0;
}
BENCH(lock, scalability) {
int i;
struct timespec t1, t2;
t1 = _timespec_real();
pthread_mutex_init(&lock, 0);
pthread_barrier_init(&barrier, 0, WAITERS + 1);
for (i = 0; i < WAITERS; ++i) {
ASSERT_EQ(0, pthread_create(t + i, 0, Waiter, 0));
}
Worker();
for (i = 0; i < WAITERS; ++i) {
ASSERT_EQ(0, pthread_join(t[i], 0));
}
pthread_barrier_destroy(&barrier);
pthread_mutex_destroy(&lock);
t2 = _timespec_real();
printf("consumed %10g seconds real time and %10g seconds cpu time\n",
_timespec_tonanos(_timespec_sub(t2, t1)) / 1e9,
(double)clock() / CLOCKS_PER_SEC);
}