Em Sat, Aug 30, 2014 at 10:53:10AM +0200, Jiri Olsa escreveu:
> On Fri, Aug 29, 2014 at 09:48:51PM +0300, Adrian Hunter wrote:
> > On 16/07/2014 9:22 p.m., Jiri Olsa wrote:
> > >On Wed, Jul 16, 2014 at 06:04:44PM +0300, Adrian Hunter wrote:
> > >>On 16/07/2014 5:25 p.m., Jiri Olsa wrote:
> > >>>On Mon, Jul 14, 2014 at 01:02:44PM +0300, Adrian Hunter wrote:
> > >>>>This enables a PMU event to be specified in the form:
> > >>>> pmu//
> > >>>>which is effectively the same as:
> > >>>> pmu/config=0/
> > >>>>This patch is a precursor to defining
> > >>>>default config for a PMU.
> > >>>I understand the need for default config, but could you please elaborate
> > >>>why do we want to parse 'pmu//' as an event string string?
> > >>Currently the parser requires the slashes to identify a PMU event
> > >>as opposed to a hardware or other kind of event.
> > >right, so why do we want to parse 'pmu//' as an event string? ;-)
> > I am not sure what you mean. Here I am using 'pmu' as a placeholder
> > for a real PMU name. So actual event strings are 'intel_bts//' or
> > 'intel_pt//' or 'intel_pt/tsc=0,noretcomp=1/'
> so the consequence of default arguments is that you can
> specify event just by the pmu name, like:
> -e intel_pt//
> which means (with default attributes):
> -e intel_pt/tsc=1,noretcomp=0/
> I guess I wanted to hear more elaboration why is this better
> than the current way we have by defining an alias, like:
> krava alias: "tsc=1,noretcomp=0"
> -e intel_pt/krava/
> which gives the same result
So you propose that we start maintaining some table of aliases that
would be installed by default, etc? "krava" would not be a good name, I
think (:-)), so in this case we would have something like:
defaults_intel_pt: "tsc=1,noretcomp=0"
-e intel_pt/defaults_intel_pt/
Which of course gets redundant/long, so, using what Adrian suggests, we
would instead not pass anything between the slashes, and that would mean
"default_" concatenated with the name of the PMU used, so it would
become:
-e intel_pt//
that would be equivalent to:
-e intel_pt/defaults_intel_pt/
and also to:
-e intel_pt/tsc=1,noretcomp=0/
?
I have not looked at the implementation, this is all just from the
information I skimmed in this thread.
- Arnaldo
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