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Remove some of the complexity from __timedwait.c. NFC #26511

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Merged
sbc100 merged 1 commit into from
Mar 25, 2026
+13 −16
Merged

Remove some of the complexity from __timedwait.c. NFC #26511

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10 changes: 3 additions & 7 deletions system/lib/libc/musl/src/thread/__timedwait.c
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Original file line number Diff line number Diff line change
Expand Up @@ -59,18 +59,14 @@ int __timedwait_cp(volatile int *addr, int val,

#ifdef __EMSCRIPTEN__
double msecsToSleep = top ? (top->tv_sec * 1000 + top->tv_nsec / 1000000.0) : INFINITY;
int is_runtime_thread = emscripten_is_main_runtime_thread();

// cp suffix in the function name means "cancellation point", so this wait can be cancelled
// by the users unless current threads cancelability is set to PTHREAD_CANCEL_DISABLE
// which may be either done by the user of __timedwait() function.
pthread_t self = pthread_self();
if (is_runtime_thread ||
self->canceldisable != PTHREAD_CANCEL_DISABLE ||
self->cancelasync) {
// Main runtime thread may need to run proxied calls, so sleep in very small slices to be responsive.
double max_ms_slice_to_sleep = is_runtime_thread ? 1 : 100;

if (self->canceldisable != PTHREAD_CANCEL_DISABLE) {
double max_ms_slice_to_sleep = 100;
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@dschuff dschuff Mar 25, 2026

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Suggested change
double max_ms_slice_to_sleep = 100;
const double max_ms_slice_to_sleep = 100;

double sleepUntilTime = emscripten_get_now() + msecsToSleep;
do {
if (self->cancel) {
Expand All @@ -79,7 +75,7 @@ int __timedwait_cp(volatile int *addr, int val,
// __pthread_testcancel(), which won't return at all.
__pthread_testcancel();
// If __pthread_testcancel does return here it means that canceldisable
// must be set to PTHREAD_CANCEL_MASKED. This appear to mean "return
// must be set to PTHREAD_CANCEL_MASKED. This appears to mean "return
// ECANCELLED to the caller". See pthread_cond_timedwait.c for the only
// use of this that I could find.
return ECANCELED;
Expand Down
3 changes: 2 additions & 1 deletion system/lib/pthread/emscripten_futex_wait.c
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Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,7 @@ static int futex_wait_main_browser_thread(volatile void* addr,
while (1) {
#ifdef __EMSCRIPTEN_PTHREADS__
if (cancelable && pthread_self()->cancel) {
__pthread_testcancel();
return -ETIMEDOUT;
}
#endif
Expand Down Expand Up @@ -213,7 +214,7 @@ int emscripten_futex_wait(volatile void *addr, uint32_t val, double max_wait_ms)
#endif
#ifdef __EMSCRIPTEN_PTHREADS__
if (cancelable && ret == ATOMICS_WAIT_TIMED_OUT && self->cancel) {
// Break out of the loop early if we were cancelled
__pthread_testcancel();
break;
}
// If remainder_ns is negative it means we want wait forever, and we don't
Expand Down
8 changes: 4 additions & 4 deletions test/codesize/test_codesize_minimal_pthreads.json
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Original file line number Diff line number Diff line change
@@ -1,10 +1,10 @@
{
"a.out.js": 7363,
"a.out.js.gz": 3604,
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"a.out.nodebug.wasm.gz": 8916,
"total": 26602,
"total_gz": 12520,
"sent": [
"a (memory)",
"b (emscripten_get_now)",
Expand Down
8 changes: 4 additions & 4 deletions test/codesize/test_codesize_minimal_pthreads_memgrowth.json
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Original file line number Diff line number Diff line change
@@ -1,10 +1,10 @@
{
"a.out.js": 7765,
"a.out.js.gz": 3810,
"a.out.nodebug.wasm": 19257,
"a.out.nodebug.wasm.gz": 8936,
"total": 27022,
"total_gz": 12746,
"a.out.nodebug.wasm": 19240,
"a.out.nodebug.wasm.gz": 8917,
"total": 27005,
"total_gz": 12727,
"sent": [
"a (memory)",
"b (emscripten_get_now)",
Expand Down
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