diff options
Diffstat (limited to 'tools/testing/selftests/powerpc/benchmarks/context_switch.c')
| -rw-r--r-- | tools/testing/selftests/powerpc/benchmarks/context_switch.c | 508 |
1 files changed, 508 insertions, 0 deletions
diff --git a/tools/testing/selftests/powerpc/benchmarks/context_switch.c b/tools/testing/selftests/powerpc/benchmarks/context_switch.c new file mode 100644 index 000000000..96554e279 --- /dev/null +++ b/tools/testing/selftests/powerpc/benchmarks/context_switch.c @@ -0,0 +1,508 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Context switch microbenchmark. + * + * Copyright (C) 2015 Anton Blanchard <anton@au.ibm.com>, IBM + */ + +#define _GNU_SOURCE +#include <errno.h> +#include <sched.h> +#include <string.h> +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> +#include <getopt.h> +#include <signal.h> +#include <assert.h> +#include <pthread.h> +#include <limits.h> +#include <sys/time.h> +#include <sys/syscall.h> +#include <sys/sysinfo.h> +#include <sys/types.h> +#include <sys/shm.h> +#include <linux/futex.h> +#ifdef __powerpc__ +#include <altivec.h> +#endif +#include "utils.h" + +static unsigned int timeout = 30; + +static int touch_vdso; +struct timeval tv; + +static int touch_fp = 1; +double fp; + +static int touch_vector = 1; +vector int a, b, c; + +#ifdef __powerpc__ +static int touch_altivec = 1; + +/* + * Note: LTO (Link Time Optimisation) doesn't play well with this function + * attribute. Be very careful enabling LTO for this test. + */ +static void __attribute__((__target__("no-vsx"))) altivec_touch_fn(void) +{ + c = a + b; +} +#endif + +static void touch(void) +{ + if (touch_vdso) + gettimeofday(&tv, NULL); + + if (touch_fp) + fp += 0.1; + +#ifdef __powerpc__ + if (touch_altivec) + altivec_touch_fn(); +#endif + + if (touch_vector) + c = a + b; + + asm volatile("# %0 %1 %2": : "r"(&tv), "r"(&fp), "r"(&c)); +} + +static void start_thread_on(void *(*fn)(void *), void *arg, unsigned long cpu) +{ + int rc; + pthread_t tid; + cpu_set_t cpuset; + pthread_attr_t attr; + + CPU_ZERO(&cpuset); + CPU_SET(cpu, &cpuset); + + rc = pthread_attr_init(&attr); + if (rc) { + errno = rc; + perror("pthread_attr_init"); + exit(1); + } + + rc = pthread_attr_setaffinity_np(&attr, sizeof(cpu_set_t), &cpuset); + if (rc) { + errno = rc; + perror("pthread_attr_setaffinity_np"); + exit(1); + } + + rc = pthread_create(&tid, &attr, fn, arg); + if (rc) { + errno = rc; + perror("pthread_create"); + exit(1); + } +} + +static void start_process_on(void *(*fn)(void *), void *arg, unsigned long cpu) +{ + int pid, ncpus; + cpu_set_t *cpuset; + size_t size; + + pid = fork(); + if (pid == -1) { + perror("fork"); + exit(1); + } + + if (pid) + return; + + ncpus = get_nprocs(); + size = CPU_ALLOC_SIZE(ncpus); + cpuset = CPU_ALLOC(ncpus); + if (!cpuset) { + perror("malloc"); + exit(1); + } + CPU_ZERO_S(size, cpuset); + CPU_SET_S(cpu, size, cpuset); + + if (sched_setaffinity(0, size, cpuset)) { + perror("sched_setaffinity"); + CPU_FREE(cpuset); + exit(1); + } + + CPU_FREE(cpuset); + fn(arg); + + exit(0); +} + +static unsigned long iterations; +static unsigned long iterations_prev; + +static void sigalrm_handler(int junk) +{ + unsigned long i = iterations; + + printf("%ld\n", i - iterations_prev); + iterations_prev = i; + + if (--timeout == 0) + kill(0, SIGUSR1); + + alarm(1); +} + +static void sigusr1_handler(int junk) +{ + exit(0); +} + +struct actions { + void (*setup)(int, int); + void *(*thread1)(void *); + void *(*thread2)(void *); +}; + +#define READ 0 +#define WRITE 1 + +static int pipe_fd1[2]; +static int pipe_fd2[2]; + +static void pipe_setup(int cpu1, int cpu2) +{ + if (pipe(pipe_fd1) || pipe(pipe_fd2)) + exit(1); +} + +static void *pipe_thread1(void *arg) +{ + signal(SIGALRM, sigalrm_handler); + alarm(1); + + while (1) { + assert(read(pipe_fd1[READ], &c, 1) == 1); + touch(); + + assert(write(pipe_fd2[WRITE], &c, 1) == 1); + touch(); + + iterations += 2; + } + + return NULL; +} + +static void *pipe_thread2(void *arg) +{ + while (1) { + assert(write(pipe_fd1[WRITE], &c, 1) == 1); + touch(); + + assert(read(pipe_fd2[READ], &c, 1) == 1); + touch(); + } + + return NULL; +} + +static struct actions pipe_actions = { + .setup = pipe_setup, + .thread1 = pipe_thread1, + .thread2 = pipe_thread2, +}; + +static void yield_setup(int cpu1, int cpu2) +{ + if (cpu1 != cpu2) { + fprintf(stderr, "Both threads must be on the same CPU for yield test\n"); + exit(1); + } +} + +static void *yield_thread1(void *arg) +{ + signal(SIGALRM, sigalrm_handler); + alarm(1); + + while (1) { + sched_yield(); + touch(); + + iterations += 2; + } + + return NULL; +} + +static void *yield_thread2(void *arg) +{ + while (1) { + sched_yield(); + touch(); + } + + return NULL; +} + +static struct actions yield_actions = { + .setup = yield_setup, + .thread1 = yield_thread1, + .thread2 = yield_thread2, +}; + +static long sys_futex(void *addr1, int op, int val1, struct timespec *timeout, + void *addr2, int val3) +{ + return syscall(SYS_futex, addr1, op, val1, timeout, addr2, val3); +} + +static unsigned long cmpxchg(unsigned long *p, unsigned long expected, + unsigned long desired) +{ + unsigned long exp = expected; + + __atomic_compare_exchange_n(p, &exp, desired, 0, + __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST); + return exp; +} + +static unsigned long xchg(unsigned long *p, unsigned long val) +{ + return __atomic_exchange_n(p, val, __ATOMIC_SEQ_CST); +} + +static int processes; + +static int mutex_lock(unsigned long *m) +{ + int c; + int flags = FUTEX_WAIT; + if (!processes) + flags |= FUTEX_PRIVATE_FLAG; + + c = cmpxchg(m, 0, 1); + if (!c) + return 0; + + if (c == 1) + c = xchg(m, 2); + + while (c) { + sys_futex(m, flags, 2, NULL, NULL, 0); + c = xchg(m, 2); + } + + return 0; +} + +static int mutex_unlock(unsigned long *m) +{ + int flags = FUTEX_WAKE; + if (!processes) + flags |= FUTEX_PRIVATE_FLAG; + + if (*m == 2) + *m = 0; + else if (xchg(m, 0) == 1) + return 0; + + sys_futex(m, flags, 1, NULL, NULL, 0); + + return 0; +} + +static unsigned long *m1, *m2; + +static void futex_setup(int cpu1, int cpu2) +{ + if (!processes) { + static unsigned long _m1, _m2; + m1 = &_m1; + m2 = &_m2; + } else { + int shmid; + void *shmaddr; + + shmid = shmget(IPC_PRIVATE, getpagesize(), SHM_R | SHM_W); + if (shmid < 0) { + perror("shmget"); + exit(1); + } + + shmaddr = shmat(shmid, NULL, 0); + if (shmaddr == (char *)-1) { + perror("shmat"); + shmctl(shmid, IPC_RMID, NULL); + exit(1); + } + + shmctl(shmid, IPC_RMID, NULL); + + m1 = shmaddr; + m2 = shmaddr + sizeof(*m1); + } + + *m1 = 0; + *m2 = 0; + + mutex_lock(m1); + mutex_lock(m2); +} + +static void *futex_thread1(void *arg) +{ + signal(SIGALRM, sigalrm_handler); + alarm(1); + + while (1) { + mutex_lock(m2); + mutex_unlock(m1); + + iterations += 2; + } + + return NULL; +} + +static void *futex_thread2(void *arg) +{ + while (1) { + mutex_unlock(m2); + mutex_lock(m1); + } + + return NULL; +} + +static struct actions futex_actions = { + .setup = futex_setup, + .thread1 = futex_thread1, + .thread2 = futex_thread2, +}; + +static struct option options[] = { + { "test", required_argument, 0, 't' }, + { "process", no_argument, &processes, 1 }, + { "timeout", required_argument, 0, 's' }, + { "vdso", no_argument, &touch_vdso, 1 }, + { "no-fp", no_argument, &touch_fp, 0 }, +#ifdef __powerpc__ + { "no-altivec", no_argument, &touch_altivec, 0 }, +#endif + { "no-vector", no_argument, &touch_vector, 0 }, + { 0, }, +}; + +static void usage(void) +{ + fprintf(stderr, "Usage: context_switch2 <options> CPU1 CPU2\n\n"); + fprintf(stderr, "\t\t--test=X\tpipe, futex or yield (default)\n"); + fprintf(stderr, "\t\t--process\tUse processes (default threads)\n"); + fprintf(stderr, "\t\t--timeout=X\tDuration in seconds to run (default 30)\n"); + fprintf(stderr, "\t\t--vdso\t\ttouch VDSO\n"); + fprintf(stderr, "\t\t--no-fp\t\tDon't touch FP\n"); +#ifdef __powerpc__ + fprintf(stderr, "\t\t--no-altivec\tDon't touch altivec\n"); +#endif + fprintf(stderr, "\t\t--no-vector\tDon't touch vector\n"); +} + +int main(int argc, char *argv[]) +{ + 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; +} |