509 lines
8.8 KiB
C
509 lines
8.8 KiB
C
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Context switch microbenchmark.
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*
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* Copyright (C) 2015 Anton Blanchard <anton@au.ibm.com>, IBM
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*/
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#define _GNU_SOURCE
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#include <errno.h>
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#include <sched.h>
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#include <string.h>
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <getopt.h>
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#include <signal.h>
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#include <assert.h>
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#include <pthread.h>
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#include <limits.h>
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#include <sys/time.h>
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#include <sys/syscall.h>
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#include <sys/sysinfo.h>
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#include <sys/types.h>
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#include <sys/shm.h>
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#include <linux/futex.h>
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#ifdef __powerpc__
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#include <altivec.h>
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#endif
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#include "utils.h"
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static unsigned int timeout = 30;
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static int touch_vdso;
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struct timeval tv;
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static int touch_fp = 1;
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double fp;
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static int touch_vector = 1;
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vector int a, b, c;
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#ifdef __powerpc__
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static int touch_altivec = 1;
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/*
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* Note: LTO (Link Time Optimisation) doesn't play well with this function
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* attribute. Be very careful enabling LTO for this test.
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*/
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static void __attribute__((__target__("no-vsx"))) altivec_touch_fn(void)
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{
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c = a + b;
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}
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#endif
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static void touch(void)
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{
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if (touch_vdso)
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gettimeofday(&tv, NULL);
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if (touch_fp)
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fp += 0.1;
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#ifdef __powerpc__
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if (touch_altivec)
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altivec_touch_fn();
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#endif
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if (touch_vector)
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c = a + b;
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asm volatile("# %0 %1 %2": : "r"(&tv), "r"(&fp), "r"(&c));
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}
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static void start_thread_on(void *(*fn)(void *), void *arg, unsigned long cpu)
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{
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int rc;
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pthread_t tid;
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cpu_set_t cpuset;
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pthread_attr_t attr;
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CPU_ZERO(&cpuset);
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CPU_SET(cpu, &cpuset);
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rc = pthread_attr_init(&attr);
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if (rc) {
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errno = rc;
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perror("pthread_attr_init");
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exit(1);
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}
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rc = pthread_attr_setaffinity_np(&attr, sizeof(cpu_set_t), &cpuset);
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if (rc) {
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errno = rc;
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perror("pthread_attr_setaffinity_np");
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exit(1);
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}
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rc = pthread_create(&tid, &attr, fn, arg);
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if (rc) {
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errno = rc;
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perror("pthread_create");
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exit(1);
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}
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}
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static void start_process_on(void *(*fn)(void *), void *arg, unsigned long cpu)
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{
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int pid, ncpus;
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cpu_set_t *cpuset;
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size_t size;
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pid = fork();
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if (pid == -1) {
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perror("fork");
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exit(1);
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}
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if (pid)
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return;
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ncpus = get_nprocs();
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size = CPU_ALLOC_SIZE(ncpus);
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cpuset = CPU_ALLOC(ncpus);
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if (!cpuset) {
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perror("malloc");
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exit(1);
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}
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CPU_ZERO_S(size, cpuset);
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CPU_SET_S(cpu, size, cpuset);
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if (sched_setaffinity(0, size, cpuset)) {
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perror("sched_setaffinity");
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CPU_FREE(cpuset);
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exit(1);
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}
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CPU_FREE(cpuset);
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fn(arg);
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exit(0);
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}
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static unsigned long iterations;
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static unsigned long iterations_prev;
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static void sigalrm_handler(int junk)
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{
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unsigned long i = iterations;
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printf("%ld\n", i - iterations_prev);
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iterations_prev = i;
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if (--timeout == 0)
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kill(0, SIGUSR1);
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alarm(1);
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}
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static void sigusr1_handler(int junk)
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{
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exit(0);
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}
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struct actions {
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void (*setup)(int, int);
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void *(*thread1)(void *);
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void *(*thread2)(void *);
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};
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#define READ 0
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#define WRITE 1
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static int pipe_fd1[2];
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static int pipe_fd2[2];
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static void pipe_setup(int cpu1, int cpu2)
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{
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if (pipe(pipe_fd1) || pipe(pipe_fd2))
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exit(1);
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}
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static void *pipe_thread1(void *arg)
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{
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signal(SIGALRM, sigalrm_handler);
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alarm(1);
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while (1) {
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assert(read(pipe_fd1[READ], &c, 1) == 1);
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touch();
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assert(write(pipe_fd2[WRITE], &c, 1) == 1);
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touch();
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iterations += 2;
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}
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return NULL;
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}
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static void *pipe_thread2(void *arg)
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{
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while (1) {
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assert(write(pipe_fd1[WRITE], &c, 1) == 1);
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touch();
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assert(read(pipe_fd2[READ], &c, 1) == 1);
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touch();
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}
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return NULL;
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}
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static struct actions pipe_actions = {
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.setup = pipe_setup,
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.thread1 = pipe_thread1,
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.thread2 = pipe_thread2,
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};
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static void yield_setup(int cpu1, int cpu2)
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{
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if (cpu1 != cpu2) {
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fprintf(stderr, "Both threads must be on the same CPU for yield test\n");
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exit(1);
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}
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}
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static void *yield_thread1(void *arg)
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{
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signal(SIGALRM, sigalrm_handler);
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alarm(1);
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while (1) {
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sched_yield();
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touch();
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iterations += 2;
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}
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return NULL;
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}
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static void *yield_thread2(void *arg)
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{
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while (1) {
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sched_yield();
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touch();
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}
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return NULL;
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}
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static struct actions yield_actions = {
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.setup = yield_setup,
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.thread1 = yield_thread1,
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.thread2 = yield_thread2,
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};
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static long sys_futex(void *addr1, int op, int val1, struct timespec *timeout,
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void *addr2, int val3)
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{
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return syscall(SYS_futex, addr1, op, val1, timeout, addr2, val3);
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}
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static unsigned long cmpxchg(unsigned long *p, unsigned long expected,
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unsigned long desired)
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{
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unsigned long exp = expected;
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__atomic_compare_exchange_n(p, &exp, desired, 0,
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__ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
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return exp;
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}
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static unsigned long xchg(unsigned long *p, unsigned long val)
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{
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return __atomic_exchange_n(p, val, __ATOMIC_SEQ_CST);
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}
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static int processes;
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static int mutex_lock(unsigned long *m)
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{
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int c;
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int flags = FUTEX_WAIT;
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if (!processes)
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flags |= FUTEX_PRIVATE_FLAG;
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c = cmpxchg(m, 0, 1);
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if (!c)
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return 0;
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if (c == 1)
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c = xchg(m, 2);
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while (c) {
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sys_futex(m, flags, 2, NULL, NULL, 0);
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c = xchg(m, 2);
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}
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return 0;
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}
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static int mutex_unlock(unsigned long *m)
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{
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int flags = FUTEX_WAKE;
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if (!processes)
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flags |= FUTEX_PRIVATE_FLAG;
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if (*m == 2)
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*m = 0;
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else if (xchg(m, 0) == 1)
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return 0;
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sys_futex(m, flags, 1, NULL, NULL, 0);
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return 0;
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}
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static unsigned long *m1, *m2;
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static void futex_setup(int cpu1, int cpu2)
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{
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if (!processes) {
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static unsigned long _m1, _m2;
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m1 = &_m1;
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m2 = &_m2;
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} else {
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int shmid;
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void *shmaddr;
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shmid = shmget(IPC_PRIVATE, getpagesize(), SHM_R | SHM_W);
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if (shmid < 0) {
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perror("shmget");
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exit(1);
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}
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shmaddr = shmat(shmid, NULL, 0);
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if (shmaddr == (char *)-1) {
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perror("shmat");
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shmctl(shmid, IPC_RMID, NULL);
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exit(1);
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}
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shmctl(shmid, IPC_RMID, NULL);
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m1 = shmaddr;
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m2 = shmaddr + sizeof(*m1);
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}
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*m1 = 0;
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*m2 = 0;
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mutex_lock(m1);
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mutex_lock(m2);
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}
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static void *futex_thread1(void *arg)
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{
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signal(SIGALRM, sigalrm_handler);
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alarm(1);
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while (1) {
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mutex_lock(m2);
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mutex_unlock(m1);
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iterations += 2;
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}
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return NULL;
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}
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static void *futex_thread2(void *arg)
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{
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while (1) {
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mutex_unlock(m2);
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mutex_lock(m1);
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}
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return NULL;
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}
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static struct actions futex_actions = {
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.setup = futex_setup,
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.thread1 = futex_thread1,
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.thread2 = futex_thread2,
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};
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static struct option options[] = {
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{ "test", required_argument, 0, 't' },
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{ "process", no_argument, &processes, 1 },
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{ "timeout", required_argument, 0, 's' },
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{ "vdso", no_argument, &touch_vdso, 1 },
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{ "no-fp", no_argument, &touch_fp, 0 },
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#ifdef __powerpc__
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{ "no-altivec", no_argument, &touch_altivec, 0 },
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#endif
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{ "no-vector", no_argument, &touch_vector, 0 },
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{ 0, },
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};
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static void usage(void)
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{
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fprintf(stderr, "Usage: context_switch2 <options> CPU1 CPU2\n\n");
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fprintf(stderr, "\t\t--test=X\tpipe, futex or yield (default)\n");
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fprintf(stderr, "\t\t--process\tUse processes (default threads)\n");
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fprintf(stderr, "\t\t--timeout=X\tDuration in seconds to run (default 30)\n");
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fprintf(stderr, "\t\t--vdso\t\ttouch VDSO\n");
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fprintf(stderr, "\t\t--no-fp\t\tDon't touch FP\n");
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#ifdef __powerpc__
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fprintf(stderr, "\t\t--no-altivec\tDon't touch altivec\n");
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#endif
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fprintf(stderr, "\t\t--no-vector\tDon't touch vector\n");
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}
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int main(int argc, char *argv[])
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{
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signed char c;
|
||
|
|
struct actions *actions = &yield_actions;
|
||
|
|
int cpu1;
|
||
|
|
int cpu2;
|
||
|
|
static void (*start_fn)(void *(*fn)(void *), void *arg, unsigned long cpu);
|
||
|
|
|
||
|
|
while (1) {
|
||
|
|
int option_index = 0;
|
||
|
|
|
||
|
|
c = getopt_long(argc, argv, "", options, &option_index);
|
||
|
|
|
||
|
|
if (c == -1)
|
||
|
|
break;
|
||
|
|
|
||
|
|
switch (c) {
|
||
|
|
case 0:
|
||
|
|
if (options[option_index].flag != 0)
|
||
|
|
break;
|
||
|
|
|
||
|
|
usage();
|
||
|
|
exit(1);
|
||
|
|
break;
|
||
|
|
|
||
|
|
case 't':
|
||
|
|
if (!strcmp(optarg, "pipe")) {
|
||
|
|
actions = &pipe_actions;
|
||
|
|
} else if (!strcmp(optarg, "yield")) {
|
||
|
|
actions = &yield_actions;
|
||
|
|
} else if (!strcmp(optarg, "futex")) {
|
||
|
|
actions = &futex_actions;
|
||
|
|
} else {
|
||
|
|
usage();
|
||
|
|
exit(1);
|
||
|
|
}
|
||
|
|
break;
|
||
|
|
|
||
|
|
case 's':
|
||
|
|
timeout = atoi(optarg);
|
||
|
|
break;
|
||
|
|
|
||
|
|
default:
|
||
|
|
usage();
|
||
|
|
exit(1);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
if (processes)
|
||
|
|
start_fn = start_process_on;
|
||
|
|
else
|
||
|
|
start_fn = start_thread_on;
|
||
|
|
|
||
|
|
if (((argc - optind) != 2)) {
|
||
|
|
cpu1 = cpu2 = pick_online_cpu();
|
||
|
|
} else {
|
||
|
|
cpu1 = atoi(argv[optind++]);
|
||
|
|
cpu2 = atoi(argv[optind++]);
|
||
|
|
}
|
||
|
|
|
||
|
|
printf("Using %s with ", processes ? "processes" : "threads");
|
||
|
|
|
||
|
|
if (actions == &pipe_actions)
|
||
|
|
printf("pipe");
|
||
|
|
else if (actions == &yield_actions)
|
||
|
|
printf("yield");
|
||
|
|
else
|
||
|
|
printf("futex");
|
||
|
|
|
||
|
|
if (!have_hwcap(PPC_FEATURE_HAS_ALTIVEC))
|
||
|
|
touch_altivec = 0;
|
||
|
|
|
||
|
|
if (!have_hwcap(PPC_FEATURE_HAS_VSX))
|
||
|
|
touch_vector = 0;
|
||
|
|
|
||
|
|
printf(" on cpus %d/%d touching FP:%s altivec:%s vector:%s vdso:%s\n",
|
||
|
|
cpu1, cpu2, touch_fp ? "yes" : "no", touch_altivec ? "yes" : "no",
|
||
|
|
touch_vector ? "yes" : "no", touch_vdso ? "yes" : "no");
|
||
|
|
|
||
|
|
/* Create a new process group so we can signal everyone for exit */
|
||
|
|
setpgid(getpid(), getpid());
|
||
|
|
|
||
|
|
signal(SIGUSR1, sigusr1_handler);
|
||
|
|
|
||
|
|
actions->setup(cpu1, cpu2);
|
||
|
|
|
||
|
|
start_fn(actions->thread1, NULL, cpu1);
|
||
|
|
start_fn(actions->thread2, NULL, cpu2);
|
||
|
|
|
||
|
|
while (1)
|
||
|
|
sleep(3600);
|
||
|
|
|
||
|
|
return 0;
|
||
|
|
}
|