Re: [PATCH v2 08/15] perf record: write trace data into mmap trace files

Jiri Olsa
2020-10-24T15:44:35Z

On Wed, Oct 21, 2020 at 07:02:56PM +0300, Alexey Budankov wrote:

SNIP

>
> record__synthesize(rec, true);
> - /* this will be recalculated during process_buildids() */
> - rec->samples = 0;
>
> if (!err) {
> if (!rec->timestamp_filename) {
> @@ -2680,9 +2709,12 @@ int cmd_record(int argc, const char **argv)
>
> }
>
> - if (rec->opts.kcore)
> + if (rec->opts.kcore || record__threads_enabled(rec))
> rec->data.is_dir = true;
>
> + if (record__threads_enabled(rec))
> + rec->opts.affinity = PERF_AFFINITY_CPU;

so all the threads will pin to cpu and back before reading?
it makes sense for one thread, but why not pin every thread
at the start?

jirka