Re: [RFC PATCHv3] perf tools: add event grouping capability to "perf stat"

[Frederic Weisbecker <fweisbec@gmail.com>]

On Thu, Nov 25, 2010 at 07:32:40AM +0100, Peter Zijlstra wrote:
> On Wed, 2010-11-24 at 17:54 -0800, Corey Ashford wrote:
> > Add the ability to create multiple event groups, each with their own leader
> > using the existing "-e <event>[,<event> ...] [-e <event>[,<event>]]"
> > syntax.  Each additional -e switch creates a new group, and each event
> > listed within a -e switch is within that group.
> > 
> > Changes since v1:
> > - Because of a flub, v2 did not contain the changes I had intended to make,
> > and instead, v2 had the same patch contents as v1.
> > - When perf stat is not supplied any events on the command line, put
> > each default event in its own group.
> 
> I like this, but could you also extend this to perf-record? its a bit
> odd to diverge between the two.
> 
> Using Stephane's latest syntax changes you could actually do something
> like:
> 
> perf record -e task-clock:freq=1000,cycles:period=0

Wouldn't this syntax clash with the flags we have on events already?

the u,k,p flags?




> 
> Which would create a group with 1 sampling counter and a counting
> counter (at which point we should probably start flipping
> PERF_SAMPLE_READ).
> 
> Matt was working on supporting that (although not through cmdline
> syntax) and teaching perf-report to cope with such output.
>