linux-kernel - Re: [PATCH 5/7] perf, tools, stat: Implement --metric-only mode

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Message-ID: <20160302154620.GA32356@krava.redhat.com>
Date:	Wed, 2 Mar 2016 16:46:20 +0100
From:	Jiri Olsa <jolsa@...hat.com>
To:	Andi Kleen <andi@...stfloor.org>
Cc:	acme@...nel.org, jolsa@...nel.org, linux-kernel@...r.kernel.org,
	Andi Kleen <ak@...ux.intel.com>
Subject: Re: [PATCH 5/7] perf, tools, stat: Implement --metric-only mode

On Wed, Mar 02, 2016 at 04:38:26PM +0100, Andi Kleen wrote:
> On Wed, Mar 02, 2016 at 12:28:42PM +0100, Jiri Olsa wrote:
> > On Tue, Mar 01, 2016 at 01:32:39PM +0100, Jiri Olsa wrote:
> > > On Mon, Feb 29, 2016 at 02:36:24PM -0800, Andi Kleen wrote:
> > > > From: Andi Kleen <ak@...ux.intel.com>
> > > > 
> > > > Add a new mode to only print metrics. Sometimes we don't care about
> > > > the raw values, just want the computed metrics. This allows more
> > > > compact printing, so with -I each sample is only a single line.
> > > > This also allows easier plotting and processing with other tools.
> > > > 
> > > > The main target is with using --topdown, but it also works with
> > > > -T and standard perf stat. A few metrics are not supported.
> > > > 
> > > > To avoiding having to hardcode all the metrics in the code it uses
> > > > a two pass approach: first compute dummy metrics and only
> > > > print the headers in the print_metric callback. Then use the callback
> > > > to print the actual values.
> > > > 
> > > > There are some additional changes
> > > > in the stat printout code to handle all metrics being on a single line.
> > > > 
> > > > One issue is that the column code doesn't know in advance what events
> > > > are not supported by the CPU, and it would be hard to find out
> > > > as this could change based on dynamic conditions. That causes
> > > > empty columns in some cases.
> > > > 
> > > > The output can be fairly wide, often you may need more than 80 columns.
> > > > 
> > > > Example:
> > > > 
> > > > % perf stat -a -I 1000 --metric-only
> > > >      1.001452803 frontend cycles idle insn per cycle       stalled cycles per insn branch-misses of all branches
> > > >      1.001452803  158.91%               0.66                2.39                    2.92%
> > > >      2.002192321  180.63%               0.76                2.08                    2.96%
> > > >      3.003088282  150.59%               0.62                2.57                    2.84%
> > > >      4.004369835  196.20%               0.98                1.62                    3.79%
> > > >      5.005227314  231.98%               0.84                1.90                    4.71%
> > > 
> > > could you please align values with the headers
> > 
> > you addressed this in new version
> 
> It's not changed. The values are aligned, but not left aligned.
> 
> Left aligned numbers would be confusing if you have multiple
> orders of magnitudes.
> 
> And it uses 7 wide fields always like the rest of perf stat
> 
> > 
> > > 
> > > also I have same issue with the stalled cycles
> > > being printed as empty in here:
> > > 
> > > [jolsa@...va perf]$ sudo ./perf stat -a -I 1000 --metric-only
> > >      1.000583845 insn per cycle       stalled cycles per insn branch-misses of all branches 
> > >      1.000583845    0.45                                         4.55%                      
> > >      2.001055181    0.86                                         4.06%                      
> > >      3.001262956    0.63                                         3.59%                      
> > 
> > but not this one..
> 
> I think that is fixed by one of the later patches. At least it works
> for me.
> 
> % perf stat -a -I 1000 --metric-only
>      1.003282611 insn per cycle       branch-misses of all branches 
>      1.003282611    0.10               22.74%                      
>      2.005159802    0.10               23.13%                     
> 
> -Andi

ugh, got confused.. you're right

jirka