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Message-ID: <20140814141056.GA7630@krava.brq.redhat.com> Date: Thu, 14 Aug 2014 16:10:57 +0200 From: Jiri Olsa <jolsa@...hat.com> To: Namhyung Kim <namhyung@...nel.org> Cc: Arnaldo Carvalho de Melo <acme@...nel.org>, Peter Zijlstra <a.p.zijlstra@...llo.nl>, Ingo Molnar <mingo@...nel.org>, Paul Mackerras <paulus@...ba.org>, Namhyung Kim <namhyung.kim@....com>, LKML <linux-kernel@...r.kernel.org>, David Ahern <dsahern@...il.com>, Andi Kleen <andi@...stfloor.org>, Frederic Weisbecker <fweisbec@...il.com>, Arun Sharma <asharma@...com>, Rodrigo Campos <rodrigo@...g.com.ar> Subject: Re: [PATCH 3/3] perf callchain: Prune misleading callchains for self entries On Thu, Aug 14, 2014 at 03:01:40PM +0900, Namhyung Kim wrote: SNIP > However, with --children feature added, it now can show all callees of > the entry. For example, "start_kernel" entry now can display it calls > rest_init and in turn cpu_idle and then cpuidle_idle_call (95.72%). > > 6.14% 0.00% swapper [kernel.kallsyms] [k] start_kernel > | > --- start_kernel > rest_init > cpu_idle > | > |--97.52%-- cpuidle_idle_call > | cpuidle_enter_tk > | | > | |--99.91%-- cpuidle_wrap_enter > | | cpuidle_enter > | | intel_idle > | --0.09%-- [...] > --2.48%-- [...] > > Note that start_kernel has no self overhead - meaning that it never > get sampled by itself but constructs such a nice callgraph. But, > sadly, if an entry has self overhead, callchain will get confused with > generated callchain (like above) and self callchains (which reversed > order) like the eariler example. > > To be consistent with other entries, I'd like to make it just to show > a single entry - itself - like below since it doesn't have callees > (children) at all. But still use the whole callchain to construct > children entries (like the start_kernel) as usual. > > 40.53% 40.53% swapper [kernel.kallsyms] [k] intel_idle > | > --- intel_idle I understand the consistency point, but I think we'd loose usefull info by cutting this off I guess I can run 'report -g callee' to find out who called intel_idle instead.. but I would not need to if the callchain stays here jirka -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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