On Tue, Mar 18, 2014 at 10:43 PM, Arnaldo Carvalho de Melo <a...@redhat.com> wrote: > Em Mon, Mar 17, 2014 at 10:45:49AM +0900, Namhyung Kim escreveu: >> Hi Don, >> >> On Fri, 14 Mar 2014 10:43:44 -0400, Don Zickus wrote: >> > When trying to capture perf data on a system running spejbb2013, >> > perf hung for about 15 minutes. This is because it took that >> > long to gather about 10,000 thread maps and process them. >> > >> > I don't think a user wants to wait that long. >> > >> > Instead, recognize that thread maps are roughly equivalent to >> > pid maps and just quickly copy those instead. >> > >> > To do this, I synthesize 'fork' events, this eventually calls >> > thread__fork() and copies the maps over. >> > >> > The overhead goes from 15 minutes down to about a few seconds. >> >> [SNIP] >> > @@ -416,6 +453,10 @@ int perf_event__synthesize_threads(struct perf_tool >> > *tool, >> > if (mmap_event == NULL) >> > goto out_free_comm; >> > >> > + fork_event = malloc(sizeof(fork_event->fork) + machine->id_hdr_size); >> > + if (fork_event == NULL) >> > + goto out_free_mmap; >> > + >> > if (machine__is_default_guest(machine)) >> > return 0; >> >> Not related to this patch, but this will causes a memory leak.. >> So I think below patch is needed on top (not sure it's also needed for >> perf_event__synthesize_thread_map() too). > > Good catch, applying it, please next time send it under separate cover, > i.e. not inside another thread.
Okay. I'll send this kind of patch in a separate thread next time. Thanks, Namhyung -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/