From 9cc63f8bcd560c760d0b12e15bba8f81c86237cf Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 14 Aug 2026 15:43:51 -0700 Subject: Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEAD Changes: Make expedited grace periods expedite normal RCU callbacks Miscellaneous fixes: * Improve diagnostic output with character task states. * Mark accesses to inform KCSAN of concurrency design. * Move from kmalloc() to kmalloc_obj(). * Documentation updates. * Improve handling of RCU deferred quiescent states. * Clean up unused function arguments and structure fields. * Reduce show_rcu_gp_kthreads() stack space. Tasks RCU updates: * Clean up after SRCU re-implementation of Tasks Trace RCU. * Mark accesses to inform KCSAN of concurrency design. * Add ->lazy_timer status to diagnostic output. * Remove an unnecessary memory barrier. * Fix a data race, courtesy of KCSAN. * Documentation updates. * Convert cond_resched_tasks_rcu_qs() from macro to static inline function. SRCU updates: * Add Rust helpers for SRCU. * Avoid losing queued work at cleanup_srcu_struct() time. Torture-test updates: * Preparation work for immediate RCU priority deboosting. * Test RCU readers from real interrupt handlers (as opposed to softirq). * Simplify code through use of cpumask_next_wrap(). * Improve diagnostic output with character task states. * Add rcutorture.nwriters parameter to allow lightweight stall testing, and rcutorture.stall_only to make doing so easier. * Test an RCU Tasks Trace grace period implying an RCU grace period. * Make RCU Tasks Trace torturing track reader batches. * Fix a data race, courtesy of KCSAN. * Plug a shuffle_tmp_mask memory leak on kthread spawn failure. --- tools/perf/bench/syscall.c | 188 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 188 insertions(+) create mode 100644 tools/perf/bench/syscall.c (limited to 'tools/perf/bench/syscall.c') diff --git a/tools/perf/bench/syscall.c b/tools/perf/bench/syscall.c new file mode 100644 index 000000000..e7dc216f7 --- /dev/null +++ b/tools/perf/bench/syscall.c @@ -0,0 +1,188 @@ +/* + * + * syscall.c + * + * syscall: Benchmark for system call performance + */ +#include "../perf.h" +#include "../util/util.h" +#include +#include "../builtin.h" +#include "bench.h" + +#include +#include +#include +#include +#include +#include +#include + +#ifndef __NR_fork +#define __NR_fork -1 +#endif + +static int loops; + +static const struct option options[] = { + OPT_INTEGER('l', "loop", &loops, "Specify number of loops"), + OPT_END() +}; + +static const char * const bench_syscall_usage[] = { + "perf bench syscall ", + NULL +}; + +static void test_fork(void) +{ + pid_t pid = fork(); + + if (pid < 0) { + fprintf(stderr, "fork failed\n"); + exit(1); + } else if (pid == 0) { + exit(0); + } else { + if (waitpid(pid, NULL, 0) < 0) { + fprintf(stderr, "waitpid failed\n"); + exit(1); + } + } +} + +static void test_execve(void) +{ + const char *pathname = "/bin/true"; + char *const argv[] = { (char *)pathname, NULL }; + pid_t pid = fork(); + + if (pid < 0) { + fprintf(stderr, "fork failed\n"); + exit(1); + } else if (pid == 0) { + execve(pathname, argv, NULL); + fprintf(stderr, "execve /bin/true failed\n"); + exit(1); + } else { + if (waitpid(pid, NULL, 0) < 0) { + fprintf(stderr, "waitpid failed\n"); + exit(1); + } + } +} + +static int bench_syscall_common(int argc, const char **argv, int syscall) +{ + struct timeval start, stop, diff; + unsigned long long result_usec = 0; + const char *name = NULL; + int i; + + switch (syscall) { + case __NR_fork: + case __NR_execve: + /* Limit default loop to 10000 times to save time */ + loops = 10000; + break; + default: + loops = 10000000; + break; + } + + /* Options -l and --loops override default above */ + argc = parse_options(argc, argv, options, bench_syscall_usage, 0); + + gettimeofday(&start, NULL); + + for (i = 0; i < loops; i++) { + switch (syscall) { + case __NR_getppid: + getppid(); + break; + case __NR_getpgid: + getpgid(0); + break; + case __NR_fork: + test_fork(); + break; + case __NR_execve: + test_execve(); + default: + break; + } + } + + gettimeofday(&stop, NULL); + timersub(&stop, &start, &diff); + + switch (syscall) { + case __NR_getppid: + name = "getppid()"; + break; + case __NR_getpgid: + name = "getpgid()"; + break; + case __NR_fork: + name = "fork()"; + break; + case __NR_execve: + name = "execve()"; + break; + default: + break; + } + + switch (bench_format) { + case BENCH_FORMAT_DEFAULT: + printf("# Executed %'d %s calls\n", loops, name); + + result_usec = diff.tv_sec * 1000000; + result_usec += diff.tv_usec; + + printf(" %14s: %lu.%03lu [sec]\n\n", "Total time", + (unsigned long) diff.tv_sec, + (unsigned long) (diff.tv_usec/1000)); + + printf(" %14lf usecs/op\n", + (double)result_usec / (double)loops); + printf(" %'14d ops/sec\n", + (int)((double)loops / + ((double)result_usec / (double)1000000))); + break; + + case BENCH_FORMAT_SIMPLE: + printf("%lu.%03lu\n", + (unsigned long) diff.tv_sec, + (unsigned long) (diff.tv_usec / 1000)); + break; + + default: + /* reaching here is something disaster */ + fprintf(stderr, "Unknown format:%d\n", bench_format); + exit(1); + break; + } + + return 0; +} + +int bench_syscall_basic(int argc, const char **argv) +{ + return bench_syscall_common(argc, argv, __NR_getppid); +} + +int bench_syscall_getpgid(int argc, const char **argv) +{ + return bench_syscall_common(argc, argv, __NR_getpgid); +} + +int bench_syscall_fork(int argc, const char **argv) +{ + return bench_syscall_common(argc, argv, __NR_fork); +} + +int bench_syscall_execve(int argc, const char **argv) +{ + return bench_syscall_common(argc, argv, __NR_execve); +} -- cgit v1.3.1