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Further optimize poll() on Windows

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Justine Tunney 2024-09-22 22:24:56 -07:00
parent 556a294363
commit 518eabadf5
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GPG key ID: BE714B4575D6E328
6 changed files with 44 additions and 64 deletions
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44
libc/calls/poll-nt.c
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@ -17,6 +17,7 @@
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/internal.h"
#include "libc/calls/sig.internal.h"
#include "libc/calls/state.internal.h"
#include "libc/calls/struct/sigset.h"
#include "libc/calls/struct/sigset.internal.h"
@ -25,6 +26,7 @@
#include "libc/calls/syscall_support-nt.internal.h"
#include "libc/intrin/atomic.h"
#include "libc/intrin/fds.h"
#include "libc/intrin/weaken.h"
#include "libc/macros.h"
#include "libc/nt/console.h"
#include "libc/nt/enum/filetype.h"
@ -41,6 +43,7 @@
#include "libc/sock/internal.h"
#include "libc/sock/struct/pollfd.h"
#include "libc/sysv/consts/o.h"
#include "libc/sysv/consts/sicode.h"
#include "libc/sysv/errfuns.h"
#include "libc/thread/posixthread.internal.h"
#ifdef __x86_64__
@ -84,7 +87,7 @@ textwindows static int sys_poll_nt_actual(struct pollfd *fds, uint64_t nfds,
struct PosixThread *pt;
int i, rc, ev, kind, gotsocks;
struct sys_pollfd_nt sockfds[64];
uint32_t cm, fi, wi, sn, pn, avail, waitfor, already_slept;
uint32_t cm, fi, sn, pn, avail, waitfor, already_slept;
// ensure revents is cleared
for (i = 0; i < nfds; ++i)
@ -228,22 +231,36 @@ textwindows static int sys_poll_nt_actual(struct pollfd *fds, uint64_t nfds,
// this ensures low latency for apps like emacs which with no sock
// here we shall actually report that something can be written too
if (!already_slept) {
if (__sigcheck(waitmask, false))
return -1;
intptr_t sigev;
if (!(sigev = CreateEvent(0, 0, 0, 0)))
return __winerr();
filehands[pn] = sigev;
pt = _pthread_self();
filehands[pn] = pt->pt_event = CreateEvent(0, 0, 0, 0);
pt->pt_event = sigev;
pt->pt_blkmask = waitmask;
atomic_store_explicit(&pt->pt_blocker, PT_BLOCKER_EVENT,
memory_order_release);
wi = WaitForMultipleObjects(pn + 1, filehands, 0, waitfor);
//!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!//
int sig = 0;
uint32_t wi = pn;
if (!_is_canceled() &&
!(_weaken(__sig_get) && (sig = _weaken(__sig_get)(waitmask))))
wi = WaitForMultipleObjects(pn + 1, filehands, 0, waitfor);
//!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!/!//
atomic_store_explicit(&pt->pt_blocker, 0, memory_order_release);
CloseHandle(filehands[pn]);
if (wi == -1u) {
CloseHandle(sigev);
if (wi == -1u)
// win32 wait failure
return __winerr();
} else if (wi == pn) {
if (wi == pn) {
// our signal event was signalled
if (__sigcheck(waitmask, false))
int handler_was_called = 0;
if (sig)
handler_was_called = _weaken(__sig_relay)(sig, SI_KERNEL, waitmask);
if (_check_cancel() == -1)
return -1;
if (handler_was_called)
return eintr();
} else if ((wi ^ kNtWaitAbandoned) < pn) {
// this is possibly because a process or thread was killed
fds[fileindices[wi ^ kNtWaitAbandoned]].revents = POLLERR_;
@ -287,8 +304,6 @@ textwindows static int sys_poll_nt_actual(struct pollfd *fds, uint64_t nfds,
} else {
// should only be possible on kNtWaitTimeout or semaphore abandoned
// keep looping for events and we'll catch timeout when appropriate
if (__sigcheck(waitmask, false))
return -1;
}
}
@ -306,6 +321,13 @@ textwindows static int sys_poll_nt_impl(struct pollfd *fds, uint64_t nfds,
uint32_t waitms;
int i, n, rc, got = 0;
// we normally don't check for signals until we decide to wait, since
// it's nice to have functions like write() be unlikely to EINTR, but
// ppoll is a function where users are surely thinking about signals,
// since ppoll actually allows them to block signals everywhere else.
if (__sigcheck(waitmask, false))
return -1;
// fast path
if (nfds <= 63)
return sys_poll_nt_actual(fds, nfds, deadline, waitmask);