Re: [RFCv2 00/48] perf tools: Add threads to record command

[Jiri Olsa]

On Fri, Sep 14, 2018 at 01:15:28PM +0200, Peter Zijlstra wrote:
> On Fri, Sep 14, 2018 at 11:40:22AM +0200, Ingo Molnar wrote:
> > In fact keeping the files separate has scalability advantages for 'perf report' and similar 
> > parsing tools: they could read all the streams in a per-CPU fashion already, from the very 
> > beginning.
> 
> Also writing to different files from different CPUs is good for record,
> less contention on the inode state (which include pagecache).

maybe I should explain a little bit more on this

we write to different (per-cpu) files during the record,
and at the end of the session, we take them and store
them inside perf.data

I don't mind having the directory instead, however we are
talking about small amount of code allowing us to keep the
data in single file.. we can always leave it to a special
command line option ;-)

jirka