mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-01-31 11:37:35 +00:00
0a79c6961f
It turns out sched_getcpu() didn't work on many platforms. So the system call now has tests and is well documented. We now employ new workarounds on platforms where it isn't supported in our malloc() implementation. It was previously the case that malloc() was only scalable on Linux/Windows for x86-64. Now the other platforms are scalable too.
104 lines
3.9 KiB
C
104 lines
3.9 KiB
C
/*-*- 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 2024 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/calls/calls.h"
|
|
#include "libc/dce.h"
|
|
#include "libc/errno.h"
|
|
#include "libc/nexgen32e/rdtscp.h"
|
|
#include "libc/nexgen32e/x86feature.h"
|
|
#include "libc/nt/struct/processornumber.h"
|
|
#include "libc/nt/synchronization.h"
|
|
#include "libc/runtime/syslib.internal.h"
|
|
#include "libc/sysv/errfuns.h"
|
|
|
|
int sys_getcpu(unsigned *opt_cpu, unsigned *opt_node, void *tcache);
|
|
|
|
/**
|
|
* Returns ID of CPU on which thread is currently scheduled.
|
|
*
|
|
* This function is supported on the following platforms:
|
|
*
|
|
* - x86-64
|
|
*
|
|
* - Linux: rdtsc
|
|
* - FreeBSD: rdtsc
|
|
* - Windows: win32
|
|
* - OpenBSD: unsupported
|
|
* - NetBSD: unsupported
|
|
* - MacOS: unsupported
|
|
*
|
|
* - aarch64
|
|
*
|
|
* - Linux: syscall
|
|
* - FreeBSD: syscall
|
|
* - MacOS: supported
|
|
*
|
|
* @return cpu number on success, or -1 w/ errno
|
|
*/
|
|
int sched_getcpu(void) {
|
|
|
|
if (IsWindows()) {
|
|
struct NtProcessorNumber pn;
|
|
GetCurrentProcessorNumberEx(&pn);
|
|
return 64 * pn.Group + pn.Number;
|
|
}
|
|
|
|
#ifdef __x86_64__
|
|
if (X86_HAVE(RDTSCP) && (IsLinux() || IsFreebsd())) {
|
|
// Only the Linux, FreeBSD, and Windows kernels can be counted upon
|
|
// to populate the TSC_AUX register with the current thread number.
|
|
unsigned tsc_aux;
|
|
rdtscp(&tsc_aux);
|
|
return TSC_AUX_CORE(tsc_aux);
|
|
}
|
|
#endif
|
|
|
|
#ifdef __aarch64__
|
|
if (IsXnu()) {
|
|
// pthread_cpu_number_np() is defined by MacOS 11.0+ (Big Sur) in
|
|
// the SDK pthread.h header file, even though there's no man page
|
|
if (__syslib && __syslib->__version >= 9) {
|
|
errno_t err;
|
|
size_t out = 0;
|
|
if ((err = __syslib->__pthread_cpu_number_np(&out))) {
|
|
errno = err;
|
|
return -1;
|
|
}
|
|
return out;
|
|
} else {
|
|
errno = ENOSYS; // upgrade your ape loader
|
|
return -1; // cc -o /usr/local/bin/ape ape/ape-m1.c
|
|
}
|
|
}
|
|
#endif
|
|
|
|
#ifdef __aarch64__
|
|
if (IsFreebsd()) {
|
|
register int x0 asm("x0");
|
|
register int x8 asm("x8") = 581; // sched_getcpu
|
|
asm volatile("svc\t0" : "=r"(x0) : "r"(x8) : "memory");
|
|
return x0;
|
|
}
|
|
#endif
|
|
|
|
unsigned cpu = 0;
|
|
int rc = sys_getcpu(&cpu, 0, 0);
|
|
if (rc == -1)
|
|
return -1;
|
|
return cpu;
|
|
}
|