Re: [PATCH 2/3 -tip] perf_counter tools: Add support to set of multiple events in one shot

Ingo Molnar
2009-06-29T03:57:45Z

* Jaswinder Singh Rajput <jaswinder@kernel.org> wrote:

> On Sun, 2009-06-28 at 15:29 +0200, Ingo Molnar wrote:
> > * Jaswinder Singh Rajput <jaswinder@kernel.org> wrote:
> >
> > > On Sat, 2009-06-27 at 18:38 +0200, Ingo Molnar wrote:
> > > > * Jaswinder Singh Rajput <jaswinder@kernel.org> wrote:
> > > >
> > > > > Add support for HARDWARE and SOFTWARE events :
> > > > > perf stat -e all-sw-events
> > > > > perf stat -e sw-events
> > > > > perf stat -e all-hw-events
> > > > > perf stat -e hw-events
> > > >
> > > > > +static struct event_type_symbol event_type_symbols[] = {
> > > > > + [PERF_TYPE_HARDWARE] = { "hw-events", "all-hw-events", },
> > > > > + [PERF_TYPE_SOFTWARE] = { "sw-events", "all-sw-events", },
> > > >
> > > > Hm, this really just special-cases and open-codes these. The better
> > > > solution is what i suggested in my review of your prior patches:
> > > > regex pattern matching.
> > > >
> > >
> > > parse_events() is responsible to parse events for 'perf stat -e'
> > > and it is parsing by parse_event_symbol()
> > >
> > > If you want to use regex pattern matching then either we should
> > > make some another option or if we need to rewrite
> > > parse_event_symbol to use regex pattern matching which will be
> > > applicable to all the events.
> >
> > As i mentioned it before, i think the most intuitive solution is to
> > extend the --event syntax with regex patterns. No new option - just
> > richer -e syntax.
> >
> > We could have this syntax:
> >
> > hw-cpu-cycles
> > hw-instructions
> > hw-cache-references
> > hw-cache-misses
> > hw-branch-instructions
> > hw-branch-misses
> > hw-bus-cycles
> >
> > sw-cpu-clock
> > sw-task-clock
> > sw-page-faults
> > sw-minor-faults
> > sw-major-faults
> > sw-context-switches
> > sw-cpu-migrations
> >
> > regex patterns like:
> >
> > hw-*
> > sw-*
> > *
> >
> > the first one would select all hardware events - the second all
> > software events - the third all events in general. But other regex
> > patterns make sense too, like:
> >
> > *branch*
> > *cache*
> > *fault*
> >
> > And as the number of generic events increases, so will regex
> > patterns become more and more useful.
> >
>
> This is a good approach, but this should be done separately
> because these will effect all the events.
>
> Currently I send patches to support multiple events in one shot
> which is adding new feature.
>
> And you telling to use regex wildcard for all the events in
> parse_event_symbol() which is enhancement and should be done in
> series of patches.

The above patterns i suggested _already cover_ 'multiple events'.

We might define further aliases like:

all := "*"
all-sw := "sw-*"

but it should all be in terms of patterns and regular expressions,
not via some hardcoded special-case thing as your posted patches
did.

Ingo