Messages in this thread | | | Date | Tue, 3 Nov 2015 07:12:04 +0900 | From | Namhyung Kim <> | Subject | Re: [RFC/PATCH 0/4] perf report: Support folded callchain output (v2) |
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Hi Arnaldo,
On Mon, Nov 02, 2015 at 06:30:21PM -0300, Arnaldo Carvalho de Melo wrote: > Em Mon, Nov 02, 2015 at 12:37:28PM -0800, Brendan Gregg escreveu: > > G'Day Namhyung, > > > > On Mon, Nov 2, 2015 at 4:57 AM, Namhyung Kim <namhyung@kernel.org> wrote: > > > Hello, > > > > > > This is what Brendan requested on the perf-users mailing list [1] to > > > support FlameGraphs [2] more efficiently. This patchset adds a few > > > more callchain options to adjust the output for it. > > > > > > At first, 'folded' output mode was added. The folded output puts all > > > calchain nodes in a line separated by semicolons, a space and the > > > value. Now it only supports --stdio as other UI provides some way of > > > folding/expanding callchains dynamically. > > > > > > The value is now can be one of 'percent', 'period', or 'count'. The > > > percent is current default output and the period is the raw number of > > > sample periods. The count is the number of samples for each callchain. > > > > > > Here's an example: > > > > > > $ perf report --no-children --show-nr-samples --stdio -g folded,count > > > ... > > > 39.93% 80 swapper [kernel.vmlinux] [k] intel_idel > > > intel_idle;cpuidle_enter_state;cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary 57 > > > intel_idle;cpuidle_enter_state;cpuidle_enter;call_cpuidle;cpu_startup_entry;rest_init;... 23 > > > > Thanks! > > > > So for the folded output I don't need the summary line (the row of > > columns printed by hist_entry__snprintf()), and don't need anything > > except folded stacks and the counts. If working with the existing > > stdio interface is making it harder than it needs to be, might it be > > I don't think it so, just add some flag asking for that > hist_entry__snprintf() to be supressed, ideas for a long option name? > > Having it as Namhyung did may have value for some people as a more > compact way to show the callchains together with the hist_entry line.
Yeah, I'd keep the hist entry line unless it's too hard to parse/filter. IMHO it's just a way to show callchains, so no need to have separate output mode..
Brendan, I guess you still need to know other info like cpu or pid, no?
And I feel like it'd be better to put the count before the callchains for consistency like below. Is it OK to you?
$ perf report --no-children --show-nr-samples --stdio -g folded,count ... 39.93% 80 swapper [kernel.vmlinux] [k] intel_idel 57 intel_idle;cpuidle_enter_state;cpuidle_enter;call_cpuidle;cpu_startup_entry;start_secondary 23 intel_idle;cpuidle_enter_state;cpuidle_enter;call_cpuidle;cpu_startup_entry;rest_init;...
> > With this in mind, do you have any other issues with Namhyung's > patchkit? An acked-by/tested-by you would be nice to have, and then we > could work out the new option to suppress that hist_entry__snprintf() > in a follow up patch. > > > easier to make it a separate interface (ui/folded), that just emitted > > the folded output? Just an idea. This existing patchset is working for > > me, I'd just be filtering the output. > > > > Having the option for percentages and periods is nice. I can envisage > > using periods (for latency flame graphs).
Glad to see you like it. :)
Thanks, Namhyung
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