mirror of
https://github.com/jart/cosmopolitan.git
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86 lines
3.9 KiB
C
86 lines
3.9 KiB
C
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2024 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/calls.h"
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#include "libc/calls/internal.h"
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#include "libc/calls/struct/timespec.h"
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#include "libc/errno.h"
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#include "libc/runtime/clktck.h"
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#include "libc/runtime/runtime.h"
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#include "libc/sysv/consts/clock.h"
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#include "libc/sysv/consts/timer.h"
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/**
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* Sleeps with higher accuracy at the cost of cpu.
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*/
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int cosmo_clock_nanosleep(int clock, int flags, const struct timespec *req,
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struct timespec *rem) {
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// pick clocks
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int time_clock;
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int sleep_clock;
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if (clock == CLOCK_REALTIME || //
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clock == CLOCK_REALTIME_PRECISE) {
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time_clock = clock;
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sleep_clock = CLOCK_REALTIME;
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} else if (clock == CLOCK_MONOTONIC || //
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clock == CLOCK_MONOTONIC_PRECISE) {
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time_clock = clock;
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sleep_clock = CLOCK_MONOTONIC;
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} else if (clock == CLOCK_REALTIME_COARSE || //
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clock == CLOCK_REALTIME_FAST) {
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return sys_clock_nanosleep(CLOCK_REALTIME, flags, req, rem);
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} else if (clock == CLOCK_MONOTONIC_COARSE || //
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clock == CLOCK_MONOTONIC_FAST) {
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return sys_clock_nanosleep(CLOCK_MONOTONIC, flags, req, rem);
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} else {
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return sys_clock_nanosleep(clock, flags, req, rem);
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}
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// sleep bulk of time in kernel
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struct timespec start, deadline, remain, waitfor, now;
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struct timespec quantum = timespec_fromnanos(1000000000 / CLK_TCK);
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clock_gettime(time_clock, &start);
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deadline = flags & TIMER_ABSTIME ? *req : timespec_add(start, *req);
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if (timespec_cmp(start, deadline) >= 0)
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return 0;
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remain = timespec_sub(deadline, start);
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if (timespec_cmp(remain, quantum) > 0) {
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waitfor = timespec_sub(remain, quantum);
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if (sys_clock_nanosleep(sleep_clock, 0, &waitfor, rem) == -1) {
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if (!flags && rem && errno == EINTR) {
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*rem = timespec_add(*rem, quantum);
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}
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return -1;
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}
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}
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// spin through final scheduling quantum
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int rc = 0;
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ftrace_enabled(-1);
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do {
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if (_check_cancel()) {
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rc = -1;
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break;
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}
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clock_gettime(time_clock, &now);
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} while (timespec_cmp(now, deadline) < 0);
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ftrace_enabled(+1);
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return rc;
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}
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