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

[Jiri Olsa]

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