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Introduce pthread_condattr_setclock()

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This is one of the few POSIX APIs that was missing. It lets you choose a
monotonic clock for your condition variables. This might improve perf on
some platforms. It might also grant more flexibility with NTP configs. I
know Qt is one project that believes it needs this. To introduce this, I
needed to change some the *NSYNC APIs, to support passing a clock param.
There's also new benchmarks, demonstrating Cosmopolitan's supremacy over
many libc implementations when it comes to mutex performance. Cygwin has
an alarmingly bad pthread_mutex_t implementation. It is so bad that they
would have been significantly better off if they'd used naive spinlocks.
This commit is contained in:
Justine Tunney 2024-09-02 23:37:50 -07:00
parent 79516bf08e
commit 3c61a541bd
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GPG key ID: BE714B4575D6E328
55 changed files with 449 additions and 155 deletions
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6
third_party/nsync/mem/nsync_mu_wait.c vendored
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@ -141,7 +141,7 @@ int nsync_mu_wait_with_deadline (nsync_mu *mu,
int (*condition) (const void *condition_arg),
const void *condition_arg,
int (*condition_arg_eq) (const void *a, const void *b),
nsync_time abs_deadline, nsync_note cancel_note) {
int clock, nsync_time abs_deadline, nsync_note cancel_note) {
lock_type *l_type;
int first_wait;
int condition_is_true;
@ -231,7 +231,7 @@ int nsync_mu_wait_with_deadline (nsync_mu *mu,
have_lock = 0;
while (ATM_LOAD_ACQ (&w->nw.waiting) != 0) { /* acquire load */
if (sem_outcome == 0) {
sem_outcome = nsync_sem_wait_with_cancel_ (w, abs_deadline,
sem_outcome = nsync_sem_wait_with_cancel_ (w, clock, abs_deadline,
cancel_note);
if (sem_outcome != 0 && ATM_LOAD (&w->nw.waiting) != 0) {
/* A timeout or cancellation occurred, and no wakeup.
@ -280,7 +280,7 @@ void nsync_mu_wait (nsync_mu *mu, int (*condition) (const void *condition_arg),
const void *condition_arg,
int (*condition_arg_eq) (const void *a, const void *b)) {
if (nsync_mu_wait_with_deadline (mu, condition, condition_arg, condition_arg_eq,
nsync_time_no_deadline, NULL) != 0) {
0, nsync_time_no_deadline, NULL) != 0) {
nsync_panic_ ("nsync_mu_wait woke but condition not true\n");
}
}