mirror of
https://github.com/jart/cosmopolitan.git
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624573207e
This change doubles the performance of thread spawning. That's thanks to our new stack manager, which allows us to avoid zeroing stacks. It gives us 15µs spawns rather than 30µs spawns on Linux. Also, pthread_exit() is faster now, since it doesn't need to acquire the pthread GIL. On NetBSD, that helps us avoid allocating too many semaphores. Even if that happens we're now able to survive semaphores running out and even memory running out, when allocating *NSYNC waiter objects. I found a lot more rare bugs in the POSIX threads runtime that could cause things to crash, if you've got dozens of threads all spawning and joining dozens of threads. I want cosmo to be world class production worthy for 2025 so happy holidays all |
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| .. | ||
| mem | ||
| testing | ||
| array.internal.h | ||
| atomic.h | ||
| atomic.internal.h | ||
| BUILD.mk | ||
| common.c | ||
| common.internal.h | ||
| compat.S | ||
| counter.h | ||
| cv.h | ||
| debug.h | ||
| heap.internal.h | ||
| LICENSE.txt | ||
| mu.c | ||
| mu.h | ||
| mu_semaphore.c | ||
| mu_semaphore.h | ||
| mu_semaphore.internal.h | ||
| mu_semaphore_futex.c | ||
| mu_semaphore_sem.c | ||
| mu_wait.h | ||
| note.h | ||
| notice.c | ||
| once.h | ||
| panic.c | ||
| races.internal.h | ||
| README.cosmo | ||
| time.c | ||
| time.h | ||
| wait_s.internal.h | ||
| waiter.h | ||
| yield.c | ||
DESCRIPTION
*NSYNC is a synchronization primitives library.
LICENSE
Apache 2.0
ORIGIN
git@github.com:google/nsync
commit ac5489682760393fe21bd2a8e038b528442412a7
Author: Mike Burrows <m3b@google.com>
Date: Wed Jun 1 16:47:52 2022 -0700
LOCAL CHANGES
- Fix nsync_mu_unlock() on Apple Silicon
- Add clock parameter to many NSYNC wait APIs
- Time APIs were so good that they're now in libc
- Double linked list API was so good that it's now in libc
- Max delay on sleep should be 20ms (not 4ms) on OpenBSD and NetBSD
- Support Apple's ulock futexes which are internal but nicer than GCD
- Ensure resources such as POSIX semaphores are are released on fork.
- Make contended mutexes go 30% faster by using C11 atomics API. This
lets us use weak cas when appropriate. It also avoids a superfluous
relaxed load on failure. This mostly impacts aarch64, not x86_64.
- Rewrote most of the semaphore and futex system call support code so
it works well with Cosmopolitan's fat runtime portability. *NSYNC's
unit test suite passes on all supported platforms. However the BSDs
currently appear to be overutilizing CPU time compared with others.
This appears to be the fault of the OSes rather than *NSYNC / Cosmo
- Support POSIX thread cancellation. APIs that wait on condition vars
are now cancellation points. In PTHREAD_CANCEL_MASKED mode they may
return ECANCELED. In PTHREAD_CANCEL_DEFERRED mode the POSIX threads
library will unwind the stack to re-acquire locks and free waiters.
On the other hand the *NSYNC APIs for mutexes will now safely block
thread cancellation, but you can still use *NSYNC notes to do that.