Re: [PATCH] perf report: show sort_order in title

From: Du, Changbin
Date: Mon Mar 13 2017 - 22:19:37 EST


On Mon, Mar 13, 2017 at 11:57:18AM -0300, Arnaldo Carvalho de Melo wrote:
> > I'll just rename this to use the tools/perf/ style for such functions,
> > making it:
> >
> > static int hists__scnprintf_sort_fields(hists, buf, size)
>
> 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
> 3.00% firefox libxul.so [.] 0x0000000001298b8d
> 1.74% swapper [kernel.vmlinux] [k] update_blocked_averages
> 1.69% qemu-system-x86 [kernel.vmlinux] [k] __fget
> 1.18% swapper [kernel.vmlinux] [k] update_wall_time
>
> 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
> 3.00% firefox libxul.so [.] 0x0000000001298b8d
> 1.74% swapper [kernel.vmlinux] [k] update_blocked_averages
> 1.69% qemu-system-x86 [kernel.vmlinux] [k] __fget
> 1.18% swapper [kernel.vmlinux] [k] update_wall_time
>
>
> I see now duplication of info, where is the value? Can you show the usecase in
> a compelling way?
>
> - Arnaldo

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
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.

--
Thanks,
Changbin Du

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