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https://github.com/jart/cosmopolitan.git
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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.
113 lines
3.8 KiB
C
113 lines
3.8 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi │
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2024 Justine Alexandra Roberts Tunney │
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│ │
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│ Permission to use, copy, modify, and/or distribute this software for │
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│ any purpose with or without fee is hereby granted, provided that the │
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│ above copyright notice and this permission notice appear in all copies. │
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│ │
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│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL │
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│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED │
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│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE │
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│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL │
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│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR │
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│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER │
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│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
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│ PERFORMANCE OF THIS SOFTWARE. │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "libc/atomic.h"
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#include "libc/calls/calls.h"
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#include "libc/dce.h"
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#include "libc/intrin/atomic.h"
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#include "libc/macros.h"
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#include "libc/runtime/runtime.h"
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#include "libc/testlib/subprocess.h"
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#include "libc/testlib/testlib.h"
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#include "libc/thread/thread.h"
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#include "libc/thread/thread2.h"
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int cpu_count;
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void SetUpOnce(void) {
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cpu_count = __get_cpu_count();
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}
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////////////////////////////////////////////////////////////////////////////////
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// AFFINITY TEST
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TEST(sched_getcpu, affinity_test) {
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if (IsXnu())
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return;
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if (IsNetbsd())
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return;
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if (IsOpenbsd())
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return;
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SPAWN(fork);
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int n = cpu_count;
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for (int i = 0; i < n; ++i) {
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cpu_set_t affinity;
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CPU_ZERO(&affinity);
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CPU_SET(i, &affinity);
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ASSERT_EQ(
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0, pthread_setaffinity_np(pthread_self(), sizeof(affinity), &affinity));
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EXPECT_EQ(i, sched_getcpu());
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}
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EXITS(0);
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}
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////////////////////////////////////////////////////////////////////////////////
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// KLUDGE TEST
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#define THREADS 2
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#define ITERATIONS 10000
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int g_hits[256];
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atomic_int g_sync;
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int call_sched_getcpu(void) {
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int res = sched_getcpu();
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ASSERT_NE(-1, res);
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ASSERT_GE(res, 0);
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ASSERT_LT(res, cpu_count);
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return res;
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}
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void *worker(void *arg) {
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int ith = (long)arg;
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int nth = THREADS;
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for (int i = 0; i < ITERATIONS; ++i) {
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// help execution of threads be interleaved
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int sync = atomic_fetch_add(&g_sync, 1);
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if (sync % nth == ith) {
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g_hits[call_sched_getcpu() % ARRAYLEN(g_hits)]++;
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}
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}
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return 0;
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}
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TEST(sched_getcpu, kludge_test) {
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#ifdef __x86_64__
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if (IsXnu())
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return;
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#endif
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if (IsNetbsd())
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return;
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if (IsOpenbsd())
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return;
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if (cpu_count < THREADS)
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return;
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pthread_t th[THREADS];
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for (int i = 0; i < THREADS; ++i)
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ASSERT_EQ(0, pthread_create(th + i, 0, worker, (void *)(long)i));
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for (int i = 0; i < THREADS; ++i)
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ASSERT_EQ(0, pthread_join(th[i], 0));
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int hit = 0;
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for (int i = 0; i < ARRAYLEN(g_hits); ++i)
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hit += !!g_hits[i];
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ASSERT_GE(hit, THREADS);
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}
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