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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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7
libc/thread/posixthread.internal.h
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@ -74,6 +74,7 @@ struct PosixThread {
int pt_flags; // 0x00: see PT_* constants
atomic_int pt_canceled; // 0x04: thread has bad beliefs
_Atomic(enum PosixThreadStatus) pt_status;
_Atomic(atomic_int *) pt_blocker;
atomic_int ptid; // transitions 0 → tid
atomic_int pt_refs; // prevents decimation
void *(*pt_start)(void *); // creation callback
@ -83,11 +84,10 @@ struct PosixThread {
struct CosmoTib *tib; // middle of tls allocation
struct Dll list; // list of threads
struct _pthread_cleanup_buffer *pt_cleanup;
_Atomic(atomic_int *) pt_blocker;
uint64_t pt_blkmask;
int64_t pt_event;
locale_t pt_locale;
jmp_buf pt_exiter;
intptr_t pt_exiter[5];
pthread_attr_t pt_attr;
atomic_bool pt_intoff;
};
@ -95,6 +95,7 @@ struct PosixThread {
typedef void (*atfork_f)(void);
extern struct Dll *_pthread_list;
extern _Atomic(unsigned) _pthread_count;
extern struct PosixThread _pthread_static;
extern _Atomic(pthread_key_dtor) _pthread_key_dtor[PTHREAD_KEYS_MAX];
@ -103,7 +104,7 @@ int _pthread_setschedparam_freebsd(int, int, const struct sched_param *);
int _pthread_tid(struct PosixThread *) libcesque;
intptr_t _pthread_syshand(struct PosixThread *) libcesque;
long _pthread_cancel_ack(void) libcesque;
void _pthread_decimate(bool) libcesque;
void _pthread_decimate(void) libcesque;
void _pthread_free(struct PosixThread *) libcesque;
void _pthread_lock(void) libcesque;
void _pthread_onfork_child(void) libcesque;