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Date: Mon, 13 Mar 2017 11:57:18 -0300
From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: changbin.du@intel.com
Cc: peterz@infradead.org, mingo@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] perf report: show sort_order in title
Message-ID: <20170313145718.GP2750@kernel.org>
References: <20170313083635.24525-1-changbin.du@intel.com>
 <20170313144714.GO2750@kernel.org>
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Em Mon, Mar 13, 2017 at 11:47:14AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Mon, Mar 13, 2017 at 04:36:35PM +0800, changbin.du@intel.com escreveu:
> > From: Changbin Du <changbin.du@intel.com>
> > 
> > In the report, how does the data sort is a important info for
> > analyser. Moreover, perf sometimes insert or append sort fields
> > automatically. Thus user may confuse how it sorts w/o reading
> > perf internal. So here print the order info to repor title.
> > 
> > Signed-off-by: Changbin Du <changbin.du@intel.com>
> > ---
> >  tools/perf/ui/browsers/hists.c | 22 ++++++++++++++++++++++
> >  1 file changed, 22 insertions(+)
> > 
> > diff --git a/tools/perf/ui/browsers/hists.c b/tools/perf/ui/browsers/hists.c
> > index fc4fb66..6c6b615 100644
> > --- a/tools/perf/ui/browsers/hists.c
> > +++ b/tools/perf/ui/browsers/hists.c
> > @@ -2194,6 +2194,25 @@ static inline bool is_report_browser(void *timer)
> >  	return timer == NULL;
> >  }
> >  
> > +static int get_sort_fields_str(struct hists *hists, char *buf, size_t size)
> 
> 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