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Make dlmalloc 2.4x faster for multithreading

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This change adds a TLS freelist for small dynamic memory allocations.
Cosmopolitan's TIB is now 512 bytes in size. Single-threaded malloc()
performance isn't impacted by this, until pthread_create() is called.
Single-threaded programs may also want to consider using:

    #include "libc/mem/tinymalloc.inc"

Which will shave 30k off the executable size and sometimes go faster.
This commit is contained in:
Justine Tunney 2024-05-28 11:13:12 -07:00
parent deaef81463
commit 07cef612c3
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GPG key ID: BE714B4575D6E328
9 changed files with 150 additions and 6 deletions
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18
libc/thread/pthread_exit.c
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@ -29,6 +29,7 @@
#include "libc/mem/mem.h"
#include "libc/runtime/internal.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/thread/posixthread.internal.h"
#include "libc/thread/thread.h"
#include "libc/thread/tls.h"
@ -130,6 +131,23 @@ wontreturn void pthread_exit(void *rc) {
}
}
#ifndef MODE_DBG
// free tls freelist
//
// 1. set lengths to -1 so free() thinks it's full
// 2. free globally by giving mallocs back to free
//
short freelen[32];
static_assert(sizeof(freelen) == sizeof(tib->tib_freelen), "");
memcpy(freelen, tib->tib_freelen, sizeof(freelen));
memset(tib->tib_freelen, -1, sizeof(freelen));
for (int i = 0; i < 32; ++i) {
if (freelen[i] > 0) {
free(tib->tib_freemem[i]);
}
}
#endif
// transition the thread to a terminated state
status = atomic_load_explicit(&pt->pt_status, memory_order_acquire);
do {