Messages in this thread | | | Subject | Re: [PATCH v2 10/15] perf record: manage thread specific data array | From | Alexei Budankov <> | Date | Mon, 26 Oct 2020 11:39:05 +0300 |
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On 24.10.2020 18:44, Jiri Olsa wrote: > On Wed, Oct 21, 2020 at 07:04:26PM +0300, Alexey Budankov wrote: >> >> Provide allocation, initialization, finalization and releasing of >> thread specific objects at thread specific data array. Allocate >> thread specific object for every data buffer making one-to-one >> relation between data buffer and a thread processing the buffer. >> Deliver event fd related signals to thread's pollfd object. >> Deliver thread control commands to ctlfd_pos fd of thread 1+. >> Deliver tool external control commands via ctlfd_pos fd of thread 0. >> >> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com> >> --- >> tools/perf/builtin-record.c | 101 ++++++++++++++++++++++++++++++++++-- >> 1 file changed, 98 insertions(+), 3 deletions(-) >> >> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c >> index 8e512096a060..89cb8e913fb3 100644 >> --- a/tools/perf/builtin-record.c >> +++ b/tools/perf/builtin-record.c >> @@ -884,6 +884,94 @@ static int record__kcore_copy(struct machine *machine, struct perf_data *data) >> return kcore_copy(from_dir, kcore_dir); >> } >> >> +static int record__alloc_thread_data(struct record *rec, struct mmap *mmaps, int nr_mmaps, >> + struct fdarray *evlist_pollfd, int ctlfd_pos) >> +{ >> + int i, j, k, nr_thread_data; >> + struct thread_data *thread_data; >> + >> + rec->nr_thread_data = nr_thread_data = nr_mmaps; >> + rec->thread_data = thread_data = zalloc(rec->nr_thread_data * sizeof(*(rec->thread_data))); >> + if (!thread_data) { >> + pr_err("Failed to allocate thread data\n"); >> + return -ENOMEM; >> + } >> + >> + for (i = 0; i < nr_thread_data; i++) { >> + short revents; >> + int pos, fd; >> + >> + thread_data[i].tid = -1; >> + >> + if (pipe(thread_data[i].comm.msg) || >> + pipe(thread_data[i].comm.ack)) { >> + pr_err("Failed to create thread comm pipes, errno %d\n", errno); >> + return -ENOMEM; >> + } > > the original code was using state flag and pthread_cond, > which I think is more readable > > https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git/commit/?h=perf/record_threads&id=a7da527ff8be69572c6d17525c03c6fe394503c8 > https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git/commit/?h=perf/record_threads&id=eb85ce4da64a885fdb6c77cfc5bd71312fe02e2a
Yes, right, but messaging scales better and that critical section to just increment global counter in memory looked as over complication.
> >> + >> + thread_data[i].maps = &mmaps[i]; >> + thread_data[i].nr_mmaps = 1; >> + >> + thread_data[i].rec = rec; >> + >> + fdarray__init(&(thread_data[i].pollfd), 64); >> + >> + for (j = 0; j < thread_data[i].nr_mmaps; j++) { >> + struct mmap *map = &(thread_data[i].maps[j]); >> + >> + for (k = 0; k < evlist_pollfd->nr; k++) { >> + if (evlist_pollfd->priv[k].ptr != map) >> + continue; >> + >> + fd = evlist_pollfd->entries[k].fd; >> + revents = evlist_pollfd->entries[k].events; >> + pos = fdarray__add(&(thread_data[i].pollfd), >> + fd, revents | POLLERR | POLLHUP, >> + fdarray_flag__default); >> + if (pos >= 0) >> + thread_data[i].pollfd.priv[pos].ptr = map; >> + else >> + return -ENOMEM; > > I added function for that: > https://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git/commit/?h=perf/record_threads&id=8aa6e68a7471b9d25af1a9eebfa9321433366a17
Ok, but it is not clone operation it is more like ordinary adding of fd into another pollfd object. It could be wrapped into a function e.g. fdarray__dup(pollfd_dst, fd_src, fd_revents)
Alexei
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