Messages in this thread | | | Subject | Re: [PATCH v6 05/20] perf record: Start threads in the beginning of trace streaming | From | Riccardo Mancini <> | Date | Fri, 04 Jun 2021 01:01:17 +0200 |
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Hi,
On Wed, 2021-05-26 at 13:52 +0300, Alexey Bayduraev wrote: > Start thread in detached state because its management is implemented > via messaging to avoid any scaling issues. Block signals prior thread > start so only main tool thread would be notified on external async > signals during data collection. Thread affinity mask is used to assign > eligible cpus for the thread to run. Wait and sync on thread start using > thread ack pipe. > > Signed-off-by: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> > --- > tools/perf/builtin-record.c | 106 +++++++++++++++++++++++++++++++++++- > 1 file changed, 105 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index 838c1f779849..88fad12cbe5b 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -1423,6 +1423,66 @@ static void record__thread_munmap_filtered(struct > fdarray *fda, int fd, > perf_mmap__put(map); > } > > +static void *record__thread(void *arg) > +{ > + enum thread_msg msg = THREAD_MSG__READY; > + bool terminate = false; > + struct fdarray *pollfd; > + int err, ctlfd_pos; > + > + thread = arg; > + thread->tid = syscall(SYS_gettid); > + > + err = write(thread->pipes.ack[1], &msg, sizeof(msg)); > + if (err == -1) > + pr_err("threads[%d]: failed to notify on start: %s", thread- > >tid, strerror(errno)); > + > + pr_debug("threads[%d]: started on cpu=%d\n", thread->tid, > sched_getcpu()); > + > + pollfd = &thread->pollfd; > + ctlfd_pos = thread->ctlfd_pos; > + > + for (;;) { > + unsigned long long hits = thread->samples; > + > + if (record__mmap_read_all(thread->rec, false) < 0 || > terminate) > + break; > + > + if (hits == thread->samples) { > + > + err = fdarray__poll(pollfd, -1); > + /* > + * Propagate error, only if there's any. Ignore > positive > + * number of returned events and interrupt error. > + */ > + if (err > 0 || (err < 0 && errno == EINTR)) > + err = 0; > + thread->waking++; > + > + if (fdarray__filter(pollfd, POLLERR | POLLHUP, > + record__thread_munmap_filtered, > NULL) == 0) > + break; > + } > + > + if (pollfd->entries[ctlfd_pos].revents & POLLHUP) { > + terminate = true; > + close(thread->pipes.msg[0]); > + pollfd->entries[ctlfd_pos].fd = -1; > + pollfd->entries[ctlfd_pos].events = 0; > + } > + > + pollfd->entries[ctlfd_pos].revents = 0; > + } > + record__mmap_read_all(thread->rec, true); > + > + err = write(thread->pipes.ack[1], &msg, sizeof(msg)); > + if (err == -1) > + pr_err("threads[%d]: failed to notify on termination: %s", > + thread->tid, strerror(errno)); > + > + return NULL; > +} > + > static void record__init_features(struct record *rec) > { > struct perf_session *session = rec->session; > @@ -1886,13 +1946,57 @@ static int record__terminate_thread(struct thread_data > *thread_data) > > static int record__start_threads(struct record *rec) > { > + int t, tt, ret = 0, nr_threads = rec->nr_threads; > struct thread_data *thread_data = rec->thread_data; > + 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 = 1; t < nr_threads; t++) { > + enum thread_msg msg = THREAD_MSG__UNDEFINED; > + > + pthread_attr_setaffinity_np(&attrs, > + > MMAP_CPU_MASK_BYTES(&(thread_data[t].mask->affinity)), > + (cpu_set_t *)(thread_data[t].mask- > >affinity.bits)); > + > + if (pthread_create(&handle, &attrs, record__thread, > &thread_data[t])) { > + for (tt = 1; tt < t; tt++) > + record__terminate_thread(&thread_data[t]); > + pr_err("Failed to start threads: %s\n", > strerror(errno)); > + ret = -1; > + goto out_err; > + } > + > + if (read(thread_data[t].pipes.ack[0], &msg, sizeof(msg)) > 0) > + pr_debug2("threads[%d]: sent %s\n", rec- > >thread_data[t].tid, > + thread_msg_tags[msg]); > + } > + > + if (nr_threads > 1) { > + sched_setaffinity(0, MMAP_CPU_MASK_BYTES(&thread_data[0].mask- > >affinity), > + (cpu_set_t *)thread_data[0].mask- > >affinity.bits); > + } > > thread = &thread_data[0]; > > pr_debug("threads[%d]: started on cpu=%d\n", thread->tid, > sched_getcpu()); > > - return 0; > +out_err: > + if (sigprocmask(SIG_SETMASK, &mask, NULL)) { > + pr_err("Failed to unblock signals on threads start: %s\n", > strerror(errno)); > + ret = -1; > + } > + > + return ret; > }
ASan complains of a memory leak of the attrs, since pthread_attr_destroy is missing. It could be added just after out_err label.
Thanks, Riccardo
> > static int record__stop_threads(struct record *rec, unsigned long *waking)
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