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On Wed, 3 Jul 2013, Dave Jones wrote:

> Linus' current tree seems to trigger this in perf_event_open on startup:
> 
>                         if (value[ptr]!='0') fprintf(stderr,"Expected 0x\n");
>                         ptr++;
>                         if (value[ptr]!='x') fprintf(stderr,"Expected 0x\n");
>                         ptr++;
> 
> I think it's from this..
> 
> /sys/bus/event_source/devices/cpu/events/mem-loads
> event=0xcd,umask=0x1,ldlat=3
> 
> Looks like that field isn't always hex.

Ugh, I would have thought they were using sprintf() or something
to generate these, but they just hard-code the string in the kernel.

  EVENT_ATTR_STR(mem-loads, mem_ld_snb, "event=0xcd,umask=0x1,ldlat=3");

The only documentation for what to expect are the lex/yacc files in
tools/perf/util/parse-events.*

I can sort of muddle my way through lex/yacc enough to see that it looks 
like both hex and decimal are allowed, so I'll update the parser for 
trinity.

I guess I should reverse-engineer what the lex/yacc is doing and document 
it in the manpage since this is an official ABI.  Fun times.


Vince Weaver
vincent.weaver@xxxxxxxxx
http://www.eece.maine.edu/~vweaver/
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