Messages in this thread | | | From | Namhyung Kim <> | Date | Thu, 15 Jul 2021 16:48:34 -0700 | Subject | Re: [RFC PATCH 03/10] perf workqueue: add threadpool start and stop functions |
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On Tue, Jul 13, 2021 at 5:11 AM Riccardo Mancini <rickyman7@gmail.com> wrote: > > This patch adds the start and stop functions, alongside the thread > function. > Each thread will run until a stop signal is received. > Furthermore, start and stop are added to the test. > > Thread management is based on the prototype from Alexey: > https://lore.kernel.org/lkml/cover.1625227739.git.alexey.v.bayduraev@linux.intel.com/ > > Suggested-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> > Signed-off-by: Riccardo Mancini <rickyman7@gmail.com> > --- > tools/perf/tests/workqueue.c | 13 ++ > tools/perf/util/workqueue/threadpool.c | 238 +++++++++++++++++++++++++ > tools/perf/util/workqueue/threadpool.h | 5 + > 3 files changed, 256 insertions(+) > > diff --git a/tools/perf/tests/workqueue.c b/tools/perf/tests/workqueue.c > index 1bd4d78c13eb3b14..be377e9897bab4e9 100644 > --- a/tools/perf/tests/workqueue.c > +++ b/tools/perf/tests/workqueue.c > @@ -10,16 +10,29 @@ struct threadpool_test_args_t { > > static int __threadpool__prepare(struct threadpool_struct **pool, int pool_size) > { > + int ret; > + > *pool = create_threadpool(pool_size); > TEST_ASSERT_VAL("threadpool creation failure", *pool != NULL); > TEST_ASSERT_VAL("threadpool size is wrong", > threadpool_size(*pool) == pool_size); > > + ret = start_threadpool(*pool); > + TEST_ASSERT_VAL("threadpool start failure", ret == 0); > + TEST_ASSERT_VAL("threadpool is not ready", threadpool_is_ready(*pool)); > + > return 0; > } > > static int __threadpool__teardown(struct threadpool_struct *pool) > { > + int ret; > + > + ret = stop_threadpool(pool); > + TEST_ASSERT_VAL("threadpool start failure", ret == 0);
s/start/stop/
> + TEST_ASSERT_VAL("stopped threadpool is ready", > + !threadpool_is_ready(pool)); > + > destroy_threadpool(pool); > > return 0; > diff --git a/tools/perf/util/workqueue/threadpool.c b/tools/perf/util/workqueue/threadpool.c > index 70c67569f956a3e2..f4635ff782b9388e 100644 > --- a/tools/perf/util/workqueue/threadpool.c > +++ b/tools/perf/util/workqueue/threadpool.c [SNIP] > +/** > + * wait_thread - receive ack from thread > + * > + * NB: call only from main thread! > + */ > +static int wait_thread(struct thread_struct *thread) > +{ > + int res; > + enum thread_msg msg = THREAD_MSG__UNDEFINED; > + > + res = read(thread->pipes.from[0], &msg, sizeof(msg)); > + if (res < 0) {
Maybe it needs to handle -EINTR.
> + pr_err("threadpool: failed to recv msg from tid=%d: %s\n", > + thread->tid, strerror(errno)); > + return -1; > + } > + if (msg != THREAD_MSG__ACK) { > + pr_err("threadpool: received unexpected msg from tid=%d: %s\n", > + thread->tid, thread_msg_tags[msg]); > + return -1; > + } > + > + pr_debug2("threadpool: received ack from tid=%d\n", thread->tid); > + > + return 0; > +} > + > +/** > + * terminate_thread - send stop signal to thread and wait for ack > + * > + * NB: call only from main thread! > + */ > +static int terminate_thread(struct thread_struct *thread) > +{ > + int res; > + enum thread_msg msg = THREAD_MSG__STOP; > + > + res = write(thread->pipes.to[1], &msg, sizeof(msg)); > + if (res < 0) { > + pr_err("threadpool: error sending stop msg to tid=%d: %s\n", > + thread->tid, strerror(errno)); > + return res; > + } > + > + res = wait_thread(thread); > + > + return res; > +} > + > +/** > + * threadpool_thread - function running on thread > + * > + * This function waits for a signal from main thread to start executing > + * a task. > + * On completion, it will go back to sleep, waiting for another signal. > + * Signals are delivered through pipes. > + */ > +static void *threadpool_thread(void *args) > +{ > + struct thread_struct *thread = (struct thread_struct *) args; > + enum thread_msg msg; > + int err; > + > + thread->tid = gettid(); > + > + pr_debug2("threadpool[%d]: started\n", thread->tid); > + > + for (;;) { > + msg = THREAD_MSG__ACK; > + err = write(thread->pipes.from[1], &msg, sizeof(msg)); > + if (err == -1) { > + pr_err("threadpool[%d]: failed to send ack: %s\n", > + thread->tid, strerror(errno)); > + break; > + } > + > + msg = THREAD_MSG__UNDEFINED; > + err = read(thread->pipes.to[0], &msg, sizeof(msg)); > + if (err < 0) { > + pr_err("threadpool[%d]: error receiving msg: %s\n", > + thread->tid, strerror(errno)); > + break; > + } > + > + if (msg != THREAD_MSG__WAKE && msg != THREAD_MSG__STOP) { > + pr_err("threadpool[%d]: received unexpected msg: %s\n", > + thread->tid, thread_msg_tags[msg]); > + break; > + } > + > + if (msg == THREAD_MSG__STOP) > + break; > + } > + > + pr_debug2("threadpool[%d]: exit\n", thread->tid); > + > + msg = THREAD_MSG__ACK; > + err = write(thread->pipes.from[1], &msg, sizeof(msg)); > + if (err == -1) { > + pr_err("threadpool[%d]: failed to send ack: %s\n", > + thread->tid, strerror(errno)); > + return NULL; > + } > + > + return NULL; > +} > + > /** > * create_threadpool - create a fixed threadpool with @n_threads threads > */ > @@ -173,3 +306,108 @@ int threadpool_size(struct threadpool_struct *pool) > { > return pool->nr_threads; > } > + > +/** > + * __start_threadpool - start all threads in the pool. > + * > + * This function does not change @pool->status. > + */ > +static int __start_threadpool(struct threadpool_struct *pool) > +{ > + int t, tt, ret = 0, nr_threads = pool->nr_threads; > + sigset_t full, mask; > + pthread_t handle; > + pthread_attr_t attrs; > + > + sigfillset(&full); > + if (sigprocmask(SIG_SETMASK, &full, &mask)) { > + pr_err("Failed to block signals on threads start: %s\n", > + strerror(errno)); > + return -1; > + } > + > + pthread_attr_init(&attrs); > + pthread_attr_setdetachstate(&attrs, PTHREAD_CREATE_DETACHED); > + > + for (t = 0; t < nr_threads; t++) { > + struct thread_struct *thread = &pool->threads[t]; > + > + if (pthread_create(&handle, &attrs, threadpool_thread, thread)) { > + for (tt = 1; tt < t; tt++) > + terminate_thread(thread); > + pr_err("Failed to start threads: %s\n", strerror(errno)); > + ret = -1; > + goto out_free_attr; > + } > + > + if (wait_thread(thread)) { > + for (tt = 1; tt <= t; tt++) > + terminate_thread(thread); > + ret = -1; > + goto out_free_attr; > + } > + }
Isn't it better doing this way?
for (t = 0; t < nr_threads; t++) { pthread_create(t) }
for (t = 0; t < nr_threads; t++) { wait_thread(t) }
Thanks, Namhyung
> + > +out_free_attr: > + pthread_attr_destroy(&attrs); > + > + if (sigprocmask(SIG_SETMASK, &mask, NULL)) { > + pr_err("Failed to unblock signals on threads start: %s\n", > + strerror(errno)); > + ret = -1; > + } > + > + return ret; > +} > +
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