Messages in this thread | | | Subject | Re: [PATCH] perf, p4: Add format attributes | From | Peter Zijlstra <> | Date | Tue, 27 Mar 2012 17:05:59 +0200 |
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On Tue, 2012-03-27 at 18:57 +0400, Cyrill Gorcunov wrote: > On Tue, Mar 27, 2012 at 04:50:42PM +0200, Peter Zijlstra wrote: > > Subject: perf, p4: Add format attributes > > From: Peter Zijlstra <a.p.zijlstra@chello.nl> > > Date: Tue Mar 27 16:19:25 CEST 2012 > > > > Steven reported his P4 not booting properly, the missing format > > attributes cause a NULL ptr deref. Cure this by adding the missing > > format specification. > > > > I took the format description out of the comment near > > p4_config_pack*() and hope that comment is still relatively > > accurate. > > > > Cc: Cyrill Gorcunov <gorcunov@openvz.org> > > Cc: Lin Ming <ming.m.lin@intel.com> > > Reported-by: Steven Rostedt <rostedt@goodmis.org> > > Tested-by: Steven Rostedt <rostedt@goodmis.org> > > Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> > > Thanks a lot, Peter! This format description is somewhat > new to me (I think I've missed when it was introduced first > time).
Yeah, its all brand-spanking new stuff.. see https://lkml.org/lkml/2012/1/16/146 , Jiri added a full fledged bison/yacc parser to perf so we can now write events like:
perf stat -e cpu/event=0xb7,umask=0x01,offcore_rsp=0x500b/
and it uses /sys/bus/event_source/devices/cpu/format/* to figure out how to convert that into perf_event_attr::config{,1,2} values.
So with this patch you could, on your P4, write:
perf stat -e cpu/cccr=0x1234,escr=0x4321,ht/
and it would construct the perf_event_attr::config value 0x92344321 for you.
I've still not actually read the P4-PMU specs, so I don't know if there's anything more convenient we can do on P4. If there's a better/more useful format representation possible, don't hesitate to send a patch! :-)
> Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Thanks!
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