mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 11:37:35 +00:00
7ff0ea8c13
pthread_mutex_lock() now uses a better algorithm which goes much faster in multithreaded environments that have lock contention. This comes at the cost of adding some fixed-cost overhead to mutex invocations. That doesn't matter for Cosmopolitan because our core libraries all encode locking operations as NOP instructions when in single-threaded mode. Overhead only applies starting the moment you first call clone().
55 lines
2.8 KiB
C
55 lines
2.8 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2022 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/calls/clock_gettime.internal.h"
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#include "libc/calls/struct/timespec.h"
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#include "libc/intrin/pthread.h"
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#include "libc/nexgen32e/rdtsc.h"
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#include "libc/nexgen32e/x86feature.h"
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#include "libc/sysv/consts/clock.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/time/clockstonanos.internal.h"
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static struct {
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pthread_once_t once;
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uint64_t base;
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struct timespec mono;
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} g_mono;
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static void sys_clock_gettime_mono_init(void) {
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clock_gettime(CLOCK_REALTIME, &g_mono.mono);
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g_mono.base = rdtsc();
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g_mono.once = true;
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}
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int sys_clock_gettime_mono(struct timespec *ts) {
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// this routine stops being monotonic after 194 years of uptime
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uint64_t nanos;
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struct timespec res;
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if (X86_HAVE(INVTSC)) {
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pthread_once(&g_mono.once, sys_clock_gettime_mono_init);
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nanos = ClocksToNanos(rdtsc(), g_mono.base);
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res = g_mono.mono;
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res.tv_sec += nanos / 1000000000;
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res.tv_nsec += nanos % 1000000000;
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*ts = res;
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return 0;
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} else {
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return einval();
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}
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}
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