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Improve Windows sleep accuracy from 15ms to 15µs

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Justine Tunney 2024-12-06 23:00:07 -08:00
parent b40140e6c5
commit b490e23d63
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GPG key ID: BE714B4575D6E328
16 changed files with 189 additions and 67 deletions
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107
libc/calls/park.c
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@ -19,65 +19,96 @@
#include "libc/calls/internal.h"
#include "libc/calls/sig.internal.h"
#include "libc/calls/struct/sigset.h"
#include "libc/calls/struct/timespec.h"
#include "libc/calls/syscall_support-nt.internal.h"
#include "libc/fmt/wintime.internal.h"
#include "libc/intrin/atomic.h"
#include "libc/intrin/weaken.h"
#include "libc/nt/enum/wait.h"
#include "libc/nt/events.h"
#include "libc/nt/runtime.h"
#include "libc/nt/synchronization.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/sicode.h"
#include "libc/sysv/errfuns.h"
#include "libc/thread/posixthread.internal.h"
#ifdef __x86_64__
// returns 0 on timeout or spurious wakeup
// returns 0 if deadline is reached
// raises EINTR if a signal delivery interrupted wait operation
// raises ECANCELED if this POSIX thread was canceled in masked mode
textwindows static int _park_thread(uint32_t msdelay, sigset_t waitmask,
textwindows static int _park_thread(struct timespec deadline, sigset_t waitmask,
bool restartable) {
struct PosixThread *pt = _pthread_self();
for (;;) {
uint32_t handl = 0;
intptr_t hands[2];
// perform the wait operation
intptr_t sigev;
if (!(sigev = CreateEvent(0, 0, 0, 0)))
return __winerr();
pt->pt_event = sigev;
pt->pt_blkmask = waitmask;
atomic_store_explicit(&pt->pt_blocker, PT_BLOCKER_EVENT,
memory_order_release);
//!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!//
int sig = 0;
uint32_t ws = 0;
if (!_is_canceled() &&
!(_weaken(__sig_get) && (sig = _weaken(__sig_get)(waitmask))))
ws = WaitForSingleObject(sigev, msdelay);
//!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!//
atomic_store_explicit(&pt->pt_blocker, 0, memory_order_release);
CloseHandle(sigev);
// create event object
intptr_t sigev;
if (!(sigev = CreateEvent(0, 0, 0, 0)))
return __winerr();
hands[handl++] = sigev;
// recursion is now safe
if (ws == -1u)
return __winerr();
int handler_was_called = 0;
if (sig)
handler_was_called = _weaken(__sig_relay)(sig, SI_KERNEL, waitmask);
if (_check_cancel())
return -1;
if (handler_was_called & SIG_HANDLED_NO_RESTART)
return eintr();
if (handler_was_called & SIG_HANDLED_SA_RESTART)
if (!restartable)
// create high precision timer if needed
if (memcmp(&deadline, &timespec_max, sizeof(struct timespec))) {
intptr_t hTimer;
if ((hTimer = CreateWaitableTimer(NULL, true, NULL))) {
int64_t due = TimeSpecToWindowsTime(deadline);
if (SetWaitableTimer(hTimer, &due, 0, NULL, NULL, false)) {
hands[handl++] = hTimer;
} else {
CloseHandle(hTimer);
}
}
}
// perform wait operation
struct PosixThread *pt = _pthread_self();
pt->pt_event = sigev;
pt->pt_blkmask = waitmask;
atomic_store_explicit(&pt->pt_blocker, PT_BLOCKER_EVENT,
memory_order_release);
//!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!//
int sig = 0;
uint32_t wi = 0;
if (!_is_canceled() &&
!(_weaken(__sig_get) && (sig = _weaken(__sig_get)(waitmask))))
wi = WaitForMultipleObjects(handl, hands, false, -1u);
//!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!//
atomic_store_explicit(&pt->pt_blocker, 0, memory_order_release);
for (int i = 0; i < handl; ++i)
CloseHandle(hands[i]);
// recursion is now safe
if (wi == 1)
return 0;
if (wi == -1u)
return __winerr();
int handler_was_called = 0;
if (!sig) {
if (_check_cancel())
return -1;
if (_weaken(__sig_get))
sig = _weaken(__sig_get)(waitmask);
}
if (sig)
handler_was_called = _weaken(__sig_relay)(sig, SI_KERNEL, waitmask);
if (_check_cancel())
return -1;
if (handler_was_called & SIG_HANDLED_NO_RESTART)
return eintr();
return 0;
if (handler_was_called & SIG_HANDLED_SA_RESTART)
if (!restartable)
return eintr();
}
}
textwindows int _park_norestart(uint32_t msdelay, sigset_t waitmask) {
return _park_thread(msdelay, waitmask, false);
textwindows int _park_norestart(struct timespec deadline, sigset_t waitmask) {
return _park_thread(deadline, waitmask, false);
}
textwindows int _park_restartable(uint32_t msdelay, sigset_t waitmask) {
return _park_thread(msdelay, waitmask, true);
textwindows int _park_restartable(struct timespec deadline, sigset_t waitmask) {
return _park_thread(deadline, waitmask, true);
}
#endif /* __x86_64__ */