selftests/powerpc: Add process creation benchmark

Signed-off-by: Nicholas Piggin <[e-mail]>
[mpe: Add SPDX, and fixup formatting]
Signed-off-by: Michael Ellerman <[e-mail]>

tools/testing/selftests/powerpc/benchmarks/.gitignore

···
 gettimeofday
 context_switch
+fork
+exec_target
 mmap_bench
 futex_bench
 null_syscall

tools/testing/selftests/powerpc/benchmarks/Makefile

···
 # SPDX-License-Identifier: GPL-2.0
-TEST_GEN_PROGS := gettimeofday context_switch mmap_bench futex_bench null_syscall
+TEST_GEN_PROGS := gettimeofday context_switch fork mmap_bench futex_bench null_syscall
+TEST_GEN_FILES := exec_target
 
 CFLAGS += -O2
 
···
 $(OUTPUT)/context_switch: ../utils.c
 $(OUTPUT)/context_switch: CFLAGS += -maltivec -mvsx -mabi=altivec
 $(OUTPUT)/context_switch: LDLIBS += -lpthread
+
+$(OUTPUT)/fork: LDLIBS += -lpthread
+
+$(OUTPUT)/exec_target: CFLAGS += -static -nostartfiles

tools/testing/selftests/powerpc/benchmarks/exec_target.c

···
+// SPDX-License-Identifier: GPL-2.0+
+
+/*
+ * Part of fork context switch microbenchmark.
+ *
+ * Copyright 2018, Anton Blanchard, IBM Corp.
+ */
+
+void _exit(int);
+void _start(void)
+{
+	_exit(0);
+}

tools/testing/selftests/powerpc/benchmarks/fork.c

···
+// SPDX-License-Identifier: GPL-2.0+
+
+/*
+ * Context switch microbenchmark.
+ *
+ * Copyright 2018, Anton Blanchard, IBM Corp.
+ */
+
+#define _GNU_SOURCE
+#include <assert.h>
+#include <errno.h>
+#include <getopt.h>
+#include <limits.h>
+#include <linux/futex.h>
+#include <pthread.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/shm.h>
+#include <sys/syscall.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+static unsigned int timeout = 30;
+
+static void set_cpu(int cpu)
+{
+	cpu_set_t cpuset;
+
+	if (cpu == -1)
+		return;
+
+	CPU_ZERO(&cpuset);
+	CPU_SET(cpu, &cpuset);
+
+	if (sched_setaffinity(0, sizeof(cpuset), &cpuset)) {
+		perror("sched_setaffinity");
+		exit(1);
+	}
+}
+
+static void start_process_on(void *(*fn)(void *), void *arg, int cpu)
+{
+	int pid;
+
+	pid = fork();
+	if (pid == -1) {
+		perror("fork");
+		exit(1);
+	}
+
+	if (pid)
+		return;
+
+	set_cpu(cpu);
+
+	fn(arg);
+
+	exit(0);
+}
+
+static int cpu;
+static int do_fork = 0;
+static int do_vfork = 0;
+static int do_exec = 0;
+static char *exec_file;
+static int exec_target = 0;
+static unsigned long iterations;
+static unsigned long iterations_prev;
+
+static void run_exec(void)
+{
+	char *const argv[] = { "./exec_target", NULL };
+
+	if (execve("./exec_target", argv, NULL) == -1) {
+		perror("execve");
+		exit(1);
+	}
+}
+
+static void bench_fork(void)
+{
+	while (1) {
+		pid_t pid = fork();
+		if (pid == -1) {
+			perror("fork");
+			exit(1);
+		}
+		if (pid == 0) {
+			if (do_exec)
+				run_exec();
+			_exit(0);
+		}
+		pid = waitpid(pid, NULL, 0);
+		if (pid == -1) {
+			perror("waitpid");
+			exit(1);
+		}
+		iterations++;
+	}
+}
+
+static void bench_vfork(void)
+{
+	while (1) {
+		pid_t pid = vfork();
+		if (pid == -1) {
+			perror("fork");
+			exit(1);
+		}
+		if (pid == 0) {
+			if (do_exec)
+				run_exec();
+			_exit(0);
+		}
+		pid = waitpid(pid, NULL, 0);
+		if (pid == -1) {
+			perror("waitpid");
+			exit(1);
+		}
+		iterations++;
+	}
+}
+
+static void *null_fn(void *arg)
+{
+	pthread_exit(NULL);
+}
+
+static void bench_thread(void)
+{
+	pthread_t tid;
+	cpu_set_t cpuset;
+	pthread_attr_t attr;
+	int rc;
+
+	rc = pthread_attr_init(&attr);
+	if (rc) {
+		errno = rc;
+		perror("pthread_attr_init");
+		exit(1);
+	}
+
+	if (cpu != -1) {
+		CPU_ZERO(&cpuset);
+		CPU_SET(cpu, &cpuset);
+
+		rc = pthread_attr_setaffinity_np(&attr, sizeof(cpu_set_t), &cpuset);
+		if (rc) {
+			errno = rc;
+			perror("pthread_attr_setaffinity_np");
+			exit(1);
+		}
+	}
+
+	while (1) {
+		rc = pthread_create(&tid, &attr, null_fn, NULL);
+		if (rc) {
+			errno = rc;
+			perror("pthread_create");
+			exit(1);
+		}
+		rc = pthread_join(tid, NULL);
+		if (rc) {
+			errno = rc;
+			perror("pthread_join");
+			exit(1);
+		}
+		iterations++;
+	}
+}
+
+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);
+}
+
+static void *bench_proc(void *arg)
+{
+	signal(SIGALRM, sigalrm_handler);
+	alarm(1);
+
+	if (do_fork)
+		bench_fork();
+	else if (do_vfork)
+		bench_vfork();
+	else
+		bench_thread();
+
+	return NULL;
+}
+
+static struct option options[] = {
+	{ "fork", no_argument, &do_fork, 1 },
+	{ "vfork", no_argument, &do_vfork, 1 },
+	{ "exec", no_argument, &do_exec, 1 },
+	{ "timeout", required_argument, 0, 's' },
+	{ "exec-target", no_argument, &exec_target, 1 },
+	{ NULL },
+};
+
+static void usage(void)
+{
+	fprintf(stderr, "Usage: fork <options> CPU\n\n");
+	fprintf(stderr, "\t\t--fork\tUse fork() (default threads)\n");
+	fprintf(stderr, "\t\t--vfork\tUse vfork() (default threads)\n");
+	fprintf(stderr, "\t\t--exec\tAlso exec() (default no exec)\n");
+	fprintf(stderr, "\t\t--timeout=X\tDuration in seconds to run (default 30)\n");
+	fprintf(stderr, "\t\t--exec-target\tInternal option for exec workload\n");
+}
+
+int main(int argc, char *argv[])
+{
+	signed char c;
+
+	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 's':
+			timeout = atoi(optarg);
+			break;
+
+		default:
+			usage();
+			exit(1);
+		}
+	}
+
+	if (do_fork && do_vfork) {
+		usage();
+		exit(1);
+	}
+	if (do_exec && !do_fork && !do_vfork) {
+		usage();
+		exit(1);
+	}
+
+	if (do_exec) {
+		char *dirname = strdup(argv[0]);
+		int i;
+		i = strlen(dirname) - 1;
+		while (i) {
+			if (dirname[i] == '/') {
+				dirname[i] = '\0';
+				if (chdir(dirname) == -1) {
+					perror("chdir");
+					exit(1);
+				}
+				break;
+			}
+			i--;
+		}
+	}
+
+	if (exec_target) {
+		exit(0);
+	}
+
+	if (((argc - optind) != 1)) {
+		cpu = -1;
+	} else {
+		cpu = atoi(argv[optind++]);
+	}
+
+	if (do_exec)
+		exec_file = argv[0];
+
+	set_cpu(cpu);
+
+	printf("Using ");
+	if (do_fork)
+		printf("fork");
+	else if (do_vfork)
+		printf("vfork");
+	else
+		printf("clone");
+
+	if (do_exec)
+		printf(" + exec");
+
+	printf(" on cpu %d\n", cpu);
+
+	/* Create a new process group so we can signal everyone for exit */
+	setpgid(getpid(), getpid());
+
+	signal(SIGUSR1, sigusr1_handler);
+
+	start_process_on(bench_proc, NULL, cpu);
+
+	while (1)
+		sleep(3600);
+
+	return 0;
+}