Messages in this thread | | | Date | Mon, 27 Aug 2018 10:43:33 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH v2 2/2]: perf record: enable asynchronous trace writing |
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On Thu, Aug 23, 2018 at 07:47:01PM +0300, Alexey Budankov wrote:
SNIP
> > static volatile int done; > @@ -528,13 +530,85 @@ static struct perf_event_header finished_round_event = { > .type = PERF_RECORD_FINISHED_ROUND, > }; > > +static int record__mmap_read_sync(int trace_fd, struct aiocb **cblocks, > + int cblocks_size, struct record *rec) > +{ > + size_t rem; > + ssize_t size; > + off_t rem_off; > + int i, aio_ret, aio_errno, do_suspend; > + struct perf_mmap *md; > + struct timespec timeout0 = { 0, 0 }; > + struct timespec timeoutS = { 0, 1000 * 1000 * 1 }; > + > + if (!cblocks_size) > + return 0; > + > + do { > + do_suspend = 0; > + nanosleep(&timeoutS, NULL); > + if (aio_suspend((const struct aiocb**)cblocks, cblocks_size, &timeout0)) { > + if (errno == EAGAIN || errno == EINTR) { > + do_suspend = 1; > + continue; > + } else { > + pr_err("failed to sync perf data, error: %m\n"); > + break; > + } > + } > + for (i = 0; i < cblocks_size; i++) {
it looks like we could set up the async write to receive the signal with the user pointer (sigev_value.sival_ptr), which would allow us to get the finished descriptor right away and we wouldn't need to iterate all of them and checking on them
jirka > + if (cblocks[i] == NULL) { > + continue; > + } > + aio_errno = aio_error(cblocks[i]); > + if (aio_errno == EINPROGRESS) { > + do_suspend = 1; > + continue; > + }
SNIP
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