Re: [PATCH] perf report: show sort_order in title
From: Du, Changbin
Date: Tue Mar 14 2017 - 22:14:28 EST
On Tue, Mar 14, 2017 at 10:04:16AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Tue, Mar 14, 2017 at 10:16:44AM +0800, Du, Changbin escreveu:
> > On Mon, Mar 13, 2017 at 11:57:18AM -0300, Arnaldo Carvalho de Melo wrote:
> > > But then, while testing,
>
> > > Before:
>
> > > $ perf report
> > > Samples: 405 of event 'cycles', Event count (approx.): 101733003
> > > Overhead Command Shared Object Symbol
> > > 11.15% swapper [kernel.vmlinux] [k] intel_idle
>
> > > Tip: Save output of perf stat using: perf stat record <target workload>
>
> > > After:
>
> > > $ perf report
> > > Samples: 405 of event 'cycles', Event count (approx.): 101733003, Sort by: Children,Overhead,Command,Shared Object,Symbol
> > > Overhead Command Shared Object Symbol
> > > 11.15% swapper [kernel.vmlinux] [k] intel_idle
>
> > > I see now duplication of info, where is the value? Can you show the usecase in
> > > a compelling way?
>
> > Thanks for trying. The key idea is to show how does the data sort, especially
> > the first sort key. When I use some GUI based perf tool, I can see how
> > my data is sorted by checking the report header status. I think this is
> > a good for browser.
>
> > You are right, the info is duplicated. I got another idea that we show a 'â' at
> > the header string and only for the first sort key. What do you think?
>
> > $ perf report
> > Samples: 405 of event 'cycles', Event count (approx.): 101733003
> > âOverhead Command Shared Object Symbol
>
> this is much more compact, but you need to make it abundantly clear what
> you are trying to achieve by showind counter examples were what we get
> on that line starting with your suggested marker isn't the sort order.
> Otherwise even a character is one too much :-)
>
Yes, I just want get know how does perf data sort. Because sometimes the
real sort order doesn't match the '-s' option I given. In this case, I
was confused about the sorting before reading into the code.
> > 11.15% swapper [kernel.vmlinux] [k] intel_idle
> > 3.00% firefox libxul.so [.] 0x0000000001298b8d
> > 1.74% swapper [kernel.vmlinux] [k] update_blocked_averages
>
> > Another idea I want to add is to support dynamic sorting. For me, I use perf to
> > analysing entire system performance, and the data is very large. Then sometimes
> > it take as long as ~10 minitues to read perf data. So I think if we can change
> > sort w/o reload data will be good.
>
> And in some cases it is even possible! I.e. if you haven't collapsed too
> much, you will not have to reprocess the file to get to the new order.
>
> BTW, have you played with:
>
> perf top --hierarchy
>
> Try it with -g and --call-graph dwarf
>
> Also try:
>
> perf report --hierarchy
>
> - Arnaldo
Sounds great! I tried '--hierarchy' option, but still don't know how to
resort the report. Could you give a hint?
--
Thanks,
Changbin Du
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