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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
commit4352b8aee98005853aa63f57d6377282de17a33f (patch)
tree27614d7a9ef05c32d089004e104364ce42324837 /tools/perf/bench/epoll-ctl.c
downloadlinux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz
linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ...
Diffstat (limited to 'tools/perf/bench/epoll-ctl.c')
-rw-r--r--tools/perf/bench/epoll-ctl.c433
1 files changed, 433 insertions, 0 deletions
diff --git a/tools/perf/bench/epoll-ctl.c b/tools/perf/bench/epoll-ctl.c
new file mode 100644
index 000000000..d66d852b9
--- /dev/null
+++ b/tools/perf/bench/epoll-ctl.c
@@ -0,0 +1,433 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Davidlohr Bueso.
+ *
+ * Benchmark the various operations allowed for epoll_ctl(2).
+ * The idea is to concurrently stress a single epoll instance
+ */
+#ifdef HAVE_EVENTFD_SUPPORT
+/* For the CLR_() macros */
+#include <string.h>
+#include <pthread.h>
+
+#include <errno.h>
+#include <inttypes.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <linux/compiler.h>
+#include <linux/kernel.h>
+#include <sys/time.h>
+#include <sys/resource.h>
+#include <sys/epoll.h>
+#include <sys/eventfd.h>
+#include <perf/cpumap.h>
+
+#include "../util/mutex.h"
+#include "../util/stat.h"
+#include <subcmd/parse-options.h>
+#include "bench.h"
+
+#include <err.h>
+
+#define printinfo(fmt, arg...) \
+ do { if (__verbose) printf(fmt, ## arg); } while (0)
+
+static unsigned int nthreads = 0;
+static unsigned int nsecs = 8;
+static bool done, __verbose, randomize;
+
+/*
+ * epoll related shared variables.
+ */
+
+/* Maximum number of nesting allowed inside epoll sets */
+#define EPOLL_MAXNESTS 4
+
+enum {
+ OP_EPOLL_ADD,
+ OP_EPOLL_MOD,
+ OP_EPOLL_DEL,
+ EPOLL_NR_OPS,
+};
+
+static int epollfd;
+static int *epollfdp;
+static bool noaffinity;
+static unsigned int nested = 0;
+
+/* amount of fds to monitor, per thread */
+static unsigned int nfds = 64;
+
+static struct mutex thread_lock;
+static unsigned int threads_starting;
+static struct stats all_stats[EPOLL_NR_OPS];
+static struct cond thread_parent, thread_worker;
+
+struct worker {
+ int tid;
+ pthread_t thread;
+ unsigned long ops[EPOLL_NR_OPS];
+ int *fdmap;
+};
+
+static const struct option options[] = {
+ OPT_UINTEGER('t', "threads", &nthreads, "Specify amount of threads"),
+ OPT_UINTEGER('r', "runtime", &nsecs, "Specify runtime (in seconds)"),
+ OPT_UINTEGER('f', "nfds", &nfds, "Specify amount of file descriptors to monitor for each thread"),
+ OPT_BOOLEAN( 'n', "noaffinity", &noaffinity, "Disables CPU affinity"),
+ OPT_UINTEGER( 'N', "nested", &nested, "Nesting level epoll hierarchy (default is 0, no nesting)"),
+ OPT_BOOLEAN( 'R', "randomize", &randomize, "Perform random operations on random fds"),
+ OPT_BOOLEAN( 'v', "verbose", &__verbose, "Verbose mode"),
+ OPT_END()
+};
+
+static const char * const bench_epoll_ctl_usage[] = {
+ "perf bench epoll ctl <options>",
+ NULL
+};
+
+static void toggle_done(int sig __maybe_unused,
+ siginfo_t *info __maybe_unused,
+ void *uc __maybe_unused)
+{
+ /* inform all threads that we're done for the day */
+ done = true;
+ gettimeofday(&bench__end, NULL);
+ timersub(&bench__end, &bench__start, &bench__runtime);
+}
+
+static void nest_epollfd(void)
+{
+ unsigned int i;
+ struct epoll_event ev;
+
+ if (nested > EPOLL_MAXNESTS)
+ nested = EPOLL_MAXNESTS;
+ printinfo("Nesting level(s): %d\n", nested);
+
+ epollfdp = calloc(nested, sizeof(int));
+ if (!epollfdp)
+ err(EXIT_FAILURE, "calloc");
+
+ for (i = 0; i < nested; i++) {
+ epollfdp[i] = epoll_create(1);
+ if (epollfd < 0)
+ err(EXIT_FAILURE, "epoll_create");
+ }
+
+ ev.events = EPOLLHUP; /* anything */
+ ev.data.u64 = i; /* any number */
+
+ for (i = nested - 1; i; i--) {
+ if (epoll_ctl(epollfdp[i - 1], EPOLL_CTL_ADD,
+ epollfdp[i], &ev) < 0)
+ err(EXIT_FAILURE, "epoll_ctl");
+ }
+
+ if (epoll_ctl(epollfd, EPOLL_CTL_ADD, *epollfdp, &ev) < 0)
+ err(EXIT_FAILURE, "epoll_ctl");
+}
+
+static inline void do_epoll_op(struct worker *w, int op, int fd)
+{
+ int error;
+ struct epoll_event ev;
+
+ ev.events = EPOLLIN;
+ ev.data.u64 = fd;
+
+ switch (op) {
+ case OP_EPOLL_ADD:
+ error = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev);
+ break;
+ case OP_EPOLL_MOD:
+ ev.events = EPOLLOUT;
+ error = epoll_ctl(epollfd, EPOLL_CTL_MOD, fd, &ev);
+ break;
+ case OP_EPOLL_DEL:
+ error = epoll_ctl(epollfd, EPOLL_CTL_DEL, fd, NULL);
+ break;
+ default:
+ error = 1;
+ break;
+ }
+
+ if (!error)
+ w->ops[op]++;
+}
+
+static inline void do_random_epoll_op(struct worker *w)
+{
+ unsigned long rnd1 = random(), rnd2 = random();
+ int op, fd;
+
+ fd = w->fdmap[rnd1 % nfds];
+ op = rnd2 % EPOLL_NR_OPS;
+
+ do_epoll_op(w, op, fd);
+}
+
+static void *workerfn(void *arg)
+{
+ unsigned int i;
+ struct worker *w = (struct worker *) arg;
+ struct timespec ts = { .tv_sec = 0,
+ .tv_nsec = 250 };
+
+ mutex_lock(&thread_lock);
+ threads_starting--;
+ if (!threads_starting)
+ cond_signal(&thread_parent);
+ cond_wait(&thread_worker, &thread_lock);
+ mutex_unlock(&thread_lock);
+
+ /* Let 'em loose */
+ do {
+ /* random */
+ if (randomize) {
+ do_random_epoll_op(w);
+ } else {
+ for (i = 0; i < nfds; i++) {
+ do_epoll_op(w, OP_EPOLL_ADD, w->fdmap[i]);
+ do_epoll_op(w, OP_EPOLL_MOD, w->fdmap[i]);
+ do_epoll_op(w, OP_EPOLL_DEL, w->fdmap[i]);
+ }
+ }
+
+ nanosleep(&ts, NULL);
+ } while (!done);
+
+ return NULL;
+}
+
+static void init_fdmaps(struct worker *w, int pct)
+{
+ unsigned int i;
+ int inc;
+ struct epoll_event ev;
+
+ if (!pct)
+ return;
+
+ inc = 100/pct;
+ for (i = 0; i < nfds; i+=inc) {
+ ev.data.fd = w->fdmap[i];
+ ev.events = EPOLLIN;
+
+ if (epoll_ctl(epollfd, EPOLL_CTL_ADD, w->fdmap[i], &ev) < 0)
+ err(EXIT_FAILURE, "epoll_ct");
+ }
+}
+
+static int do_threads(struct worker *worker, struct perf_cpu_map *cpu)
+{
+ pthread_attr_t thread_attr, *attrp = NULL;
+ cpu_set_t *cpuset;
+ unsigned int i, j;
+ int ret = 0;
+ int nrcpus;
+ size_t size;
+
+ if (!noaffinity)
+ pthread_attr_init(&thread_attr);
+
+ nrcpus = cpu__max_cpu().cpu;
+ cpuset = CPU_ALLOC(nrcpus);
+ BUG_ON(!cpuset);
+ size = CPU_ALLOC_SIZE(nrcpus);
+
+ for (i = 0; i < nthreads; i++) {
+ struct worker *w = &worker[i];
+
+ w->tid = i;
+ w->fdmap = calloc(nfds, sizeof(int));
+ if (!w->fdmap)
+ return 1;
+
+ for (j = 0; j < nfds; j++) {
+ w->fdmap[j] = eventfd(0, EFD_NONBLOCK);
+ if (w->fdmap[j] < 0)
+ err(EXIT_FAILURE, "eventfd");
+ }
+
+ /*
+ * Lets add 50% of the fdmap to the epoll instance, and
+ * do it before any threads are started; otherwise there is
+ * an initial bias of the call failing (mod and del ops).
+ */
+ if (randomize)
+ init_fdmaps(w, 50);
+
+ if (!noaffinity) {
+ CPU_ZERO_S(size, cpuset);
+ CPU_SET_S(perf_cpu_map__cpu(cpu, i % perf_cpu_map__nr(cpu)).cpu,
+ size, cpuset);
+
+ ret = pthread_attr_setaffinity_np(&thread_attr, size, cpuset);
+ if (ret) {
+ CPU_FREE(cpuset);
+ err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
+ }
+
+ attrp = &thread_attr;
+ }
+
+ ret = pthread_create(&w->thread, attrp, workerfn,
+ (void *)(struct worker *) w);
+ if (ret) {
+ CPU_FREE(cpuset);
+ err(EXIT_FAILURE, "pthread_create");
+ }
+ }
+
+ CPU_FREE(cpuset);
+ if (!noaffinity)
+ pthread_attr_destroy(&thread_attr);
+
+ return ret;
+}
+
+static void print_summary(void)
+{
+ int i;
+ unsigned long avg[EPOLL_NR_OPS];
+ double stddev[EPOLL_NR_OPS];
+
+ for (i = 0; i < EPOLL_NR_OPS; i++) {
+ avg[i] = avg_stats(&all_stats[i]);
+ stddev[i] = stddev_stats(&all_stats[i]);
+ }
+
+ printf("\nAveraged %ld ADD operations (+- %.2f%%)\n",
+ avg[OP_EPOLL_ADD], rel_stddev_stats(stddev[OP_EPOLL_ADD],
+ avg[OP_EPOLL_ADD]));
+ printf("Averaged %ld MOD operations (+- %.2f%%)\n",
+ avg[OP_EPOLL_MOD], rel_stddev_stats(stddev[OP_EPOLL_MOD],
+ avg[OP_EPOLL_MOD]));
+ printf("Averaged %ld DEL operations (+- %.2f%%)\n",
+ avg[OP_EPOLL_DEL], rel_stddev_stats(stddev[OP_EPOLL_DEL],
+ avg[OP_EPOLL_DEL]));
+}
+
+int bench_epoll_ctl(int argc, const char **argv)
+{
+ int j, ret = 0;
+ struct sigaction act;
+ struct worker *worker = NULL;
+ struct perf_cpu_map *cpu;
+ struct rlimit rl, prevrl;
+ unsigned int i;
+
+ argc = parse_options(argc, argv, options, bench_epoll_ctl_usage, 0);
+ if (argc) {
+ usage_with_options(bench_epoll_ctl_usage, options);
+ exit(EXIT_FAILURE);
+ }
+
+ memset(&act, 0, sizeof(act));
+ sigfillset(&act.sa_mask);
+ act.sa_sigaction = toggle_done;
+ sigaction(SIGINT, &act, NULL);
+
+ cpu = perf_cpu_map__new_online_cpus();
+ if (!cpu)
+ goto errmem;
+
+ /* a single, main epoll instance */
+ epollfd = epoll_create(1);
+ if (epollfd < 0)
+ err(EXIT_FAILURE, "epoll_create");
+
+ /*
+ * Deal with nested epolls, if any.
+ */
+ if (nested)
+ nest_epollfd();
+
+ /* default to the number of CPUs */
+ if (!nthreads)
+ nthreads = perf_cpu_map__nr(cpu);
+
+ worker = calloc(nthreads, sizeof(*worker));
+ if (!worker)
+ goto errmem;
+
+ if (getrlimit(RLIMIT_NOFILE, &prevrl))
+ err(EXIT_FAILURE, "getrlimit");
+ rl.rlim_cur = rl.rlim_max = nfds * nthreads * 2 + 50;
+ printinfo("Setting RLIMIT_NOFILE rlimit from %" PRIu64 " to: %" PRIu64 "\n",
+ (uint64_t)prevrl.rlim_max, (uint64_t)rl.rlim_max);
+ if (setrlimit(RLIMIT_NOFILE, &rl) < 0)
+ err(EXIT_FAILURE, "setrlimit");
+
+ printf("Run summary [PID %d]: %d threads doing epoll_ctl ops "
+ "%d file-descriptors for %d secs.\n\n",
+ getpid(), nthreads, nfds, nsecs);
+
+ for (i = 0; i < EPOLL_NR_OPS; i++)
+ init_stats(&all_stats[i]);
+
+ mutex_init(&thread_lock);
+ cond_init(&thread_parent);
+ cond_init(&thread_worker);
+
+ threads_starting = nthreads;
+
+ gettimeofday(&bench__start, NULL);
+
+ do_threads(worker, cpu);
+
+ mutex_lock(&thread_lock);
+ while (threads_starting)
+ cond_wait(&thread_parent, &thread_lock);
+ cond_broadcast(&thread_worker);
+ mutex_unlock(&thread_lock);
+
+ sleep(nsecs);
+ toggle_done(0, NULL, NULL);
+ printinfo("main thread: toggling done\n");
+
+ for (i = 0; i < nthreads; i++) {
+ ret = pthread_join(worker[i].thread, NULL);
+ if (ret)
+ err(EXIT_FAILURE, "pthread_join");
+ }
+
+ /* cleanup & report results */
+ cond_destroy(&thread_parent);
+ cond_destroy(&thread_worker);
+ mutex_destroy(&thread_lock);
+
+ for (i = 0; i < nthreads; i++) {
+ unsigned long t[EPOLL_NR_OPS];
+
+ for (j = 0; j < EPOLL_NR_OPS; j++) {
+ t[j] = worker[i].ops[j];
+ update_stats(&all_stats[j], t[j]);
+ }
+
+ if (nfds == 1)
+ printf("[thread %2d] fdmap: %p [ add: %04ld; mod: %04ld; del: %04lds ops ]\n",
+ worker[i].tid, &worker[i].fdmap[0],
+ t[OP_EPOLL_ADD], t[OP_EPOLL_MOD], t[OP_EPOLL_DEL]);
+ else
+ printf("[thread %2d] fdmap: %p ... %p [ add: %04ld ops; mod: %04ld ops; del: %04ld ops ]\n",
+ worker[i].tid, &worker[i].fdmap[0],
+ &worker[i].fdmap[nfds-1],
+ t[OP_EPOLL_ADD], t[OP_EPOLL_MOD], t[OP_EPOLL_DEL]);
+ }
+
+ print_summary();
+
+ close(epollfd);
+ perf_cpu_map__put(cpu);
+ for (i = 0; i < nthreads; i++)
+ free(worker[i].fdmap);
+
+ free(worker);
+ return ret;
+errmem:
+ err(EXIT_FAILURE, "calloc");
+}
+#endif // HAVE_EVENTFD_SUPPORT