Messages in this thread | | | Date | Thu, 3 May 2012 22:05:18 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH 9/9] perf tool: Add pmu event alias support |
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On Thu, May 03, 2012 at 01:24:21PM +0200, Peter Zijlstra wrote: > On Thu, 2012-05-03 at 12:56 +0200, Jiri Olsa wrote: > > - in sysfs you would have directory with aliases (now called 'events') > > - each alias is sysfs dir, with file attrs: > > file name = term name, file value = term value > > eg.: > > events/ > > CAS_COUNT_RD/ > > # files: > > config - value 1 > > config1 - value 2 > > mask - value ... > > I'd prefer the thing Yan proposed (if the sysfs folks let us), > > $foo/events/QHL_REQUEST_REMOTE_READS > > with contents: "event=0x20,umask=0x4" > > > this way it's also possible to add extra terms to existing alias > > in command line if needed... might be handy > > > That should always be possible, if you modify the parser to take things > like: > > event=0x20,umask=0x4,event=0x21 > > and have latter values override earlier values, so it collapses into: > > umask=0x4,event=0x21 > > you can simply take whatever comes out of the event file and stick extra > bits at the end.
I discussed this with Peter on irc, so I'll try to sum it up
we have following options so far:
with event alias 'al' with definition 'config=1,config1=1,config2=2'
1) inside parse_events_add_pmu function once alias term is detected as part of event definition 'pmu/al/mod' we construct new event 'pmu/config=1,config1=1,config2=2/mod' and rerun the event parser on that
2) inside parse_events_add_pmu function once alias term is detected as part of event definition 'pmu/al/mod' we replace that term with list of terms for that alias definition and run perf_pmu__config with this new term list
3) during bison/flex processing have option 2) embeded inside flex/bison rules. Once alias term is detected, insert the aliased terms directly to the list of terms, not replacing expos as in option 2.
- option 1 is currently implemented - options 2 and 3 requires the aliased config is loaded/parsed from pmu sysfs tree in form of terms list - option 3 is a little fuzzy for me now on how to integrate this with flex/bison
My interest here is to go with option 2 or 3 if possible - preferrably 2 ;), because I think it's better/cleaner to deal with terms in one place once they are parsed - in parse_events_add_pmu function.
I think there's no need to re run the whole parser (option 1) when we have the whole thing ready by adding just extra terms.
thoughts?
thanks, jirka
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