Messages in this thread | | | Date | Tue, 26 Apr 2016 23:55:36 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH/RFC v3] perf core: Allow setting up max frame stack depth via sysctl |
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On Tue, Apr 26, 2016 at 06:05:00PM -0300, Arnaldo Carvalho de Melo wrote: > > I started with max depth = 512, and even that was still truncated, and > > had to profile again at 1024 to capture the full stacks. Seems to
^^^^^^
> > generally match the flame graph I generated with V1, which made me > > want to check that I'm running the new patch, and am: > > > > # grep six_hundred_forty_kb /proc/kallsyms > > ffffffff81c431e0 d six_hundred_forty_kb > > > > I was mucking around and was able to get "corrupted callchain. > > skipping..." errors, but these look to be expected -- that was > > Yeah, thanks for testing! > > And since you talked about userspace without frame pointers, have you > played with '--call-graph lbr'?
That seems to be at odds with his requirements; he needs 1024 entries to capture full stacks, LBR is limited to 16/32 or so entries. That's 2 orders of magnitude difference.
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