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Make threads faster and more reliable

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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
This commit is contained in:
Justine Tunney 2024-12-18 04:59:02 -08:00
parent 906bd06a5a
commit 624573207e
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GPG key ID: BE714B4575D6E328
51 changed files with 1006 additions and 321 deletions
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56
libc/thread/mapstack.c Normal file
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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2022 Justine Alexandra Roberts Tunney │
│ │
│ Permission to use, copy, modify, and/or distribute this software for │
│ any purpose with or without fee is hereby granted, provided that the │
│ above copyright notice and this permission notice appear in all copies. │
│ │
│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/cosmo.h"
#include "libc/errno.h"
#include "libc/runtime/stack.h"
/**
* Allocates stack.
*
* The size of your returned stack is always GetStackSize().
*
* The bottom 4096 bytes of your stack can't be used, since it's always
* reserved for a read-only guard page. With ASAN it'll be poisoned too.
*
* The top 16 bytes of a stack can't be used due to openbsd:stackbound
* and those bytes are also poisoned under ASAN build modes.
*
* @return stack bottom address on success, or null w/ errno
*/
void *NewCosmoStack(void) {
void *stackaddr;
size_t stacksize = GetStackSize();
size_t guardsize = GetGuardSize();
errno_t err = cosmo_stack_alloc(&stacksize, &guardsize, &stackaddr);
if (!err)
return stackaddr;
errno = err;
return 0;
}
/**
* Frees stack.
*
* @param stackaddr was allocated by NewCosmoStack()
* @return 0 on success, or -1 w/ errno
*/
int FreeCosmoStack(void *stackaddr) {
cosmo_stack_free(stackaddr, GetStackSize(), GetGuardSize());
return 0;
}