Hi Ingo, On Tue, Oct 24, 2017 at 03:25:23PM +0200, Ingo Molnar wrote: > > * Arnaldo Carvalho de Melo <a...@kernel.org> wrote: > > > Em Tue, Oct 24, 2017 at 02:59:44PM +0200, Ingo Molnar escreveu: > > > > > > * Jiri Olsa <jo...@redhat.com> wrote: > > > > > > > I recently made some changes on threaded record, which are based > > > > on Namhyungs time* API, which is needed to read/sort the data afterwards > > > > > > > > but I wasn't able to get any substantial and constant reduce of LOST > > > > events > > > > and then I got sidetracked and did not finish, but it's in here: > > > > > > So, in the context of system-wide profiling, the way that would work best > > > I think > > > is the following: > > > > > > thread #0 binds itself to CPU#0 (via sched_setaffinity) and creates a > > > per-CPU event on CPU#0 > > > thread #1 binds itself to CPU#1 (via sched_setaffinity) and creates a > > > per-CPU event on CPU#1 > > > thread #2 binds itself to CPU#2 (via sched_setaffinity) and creates a > > > per-CPU event on CPU#2 > > > > Right, that is how I think it should be done as well, and those will > > just dump on separate files, in a per session directory, with an extra > > file for the session details, in what is now the header. > > Yes. Also note how easy to examine such a directory structure is - I'd > suggest > making all the session details textual eventually. I.e. only the ring-buffers > should be binary, the rest should be arch-independent text encoding. > > It's also very extensible.
Agreed. Also for multithread work, conversion to directory should be the first step IMHO. Thanks, Namhyung > > > Later, the same thing happens at processing time, this time we'll have > > contention to access global thread state, the need for rounds of > > PERF_SAMPLE_TIME based ordering, like what we have now in the > > tools/perf/util/ordered-events.[ch] code, etc. > > > > This works for both 'report', 'script', 'top', 'trace', etc, as is > > basically the model we already have. All the work that was done for > > refcounting the thread, map, etc as well as locking those rbtrees would > > finally be taken full advantage of. > > Yeah, cool! > > Thanks, > > Ingo
