Re: [PATCHv4 0/9] perf tool: parser generator for events parsing

From: Peter Zijlstra
Date: Wed Feb 15 2012 - 06:18:44 EST


On Wed, 2012-02-15 at 10:24 +0100, Jiri Olsa wrote:
> On Tue, Feb 14, 2012 at 10:03:11PM +0100, Peter Zijlstra wrote:

> > These would be: period, config, config1, config2 and stephane's new
> > branch_sample_type, although that might want to get a shorter name.
>
> right, for pmu/.../ syntax there are allowed only fields from 'format'
> directory are so far.. with exceptions like: cycles/period=100000/
>
> so I'll hardcode following config fields:
> config
> config1
> config2
> period
> branch_sample_type (branch, branch_type, branch_st ???)

Uhmm,.. Stephane any particular preference on this?

> to be used in xxx/.../ syntax
>
> also we need to choose some strategy of format field name shadowing
> with hardcoded fields:
>
> - BUILD_BUG in kernel PMU_FORMAT_ATTR
> - not allowed.. report error in perf runtime
> - allowed - hardcoded field have precedence
> - allowed - format field values have precedence
>
> I'd say either allow shadowing(with whatever precedence we this is better),
> or have the BUILD_BUG line in kernel..

I agree, if we can get the BUILD_BUG thing working that might be the
best option, otherwise we can do the precedence thing. We could even add
a syntax to resolve the namespace conflict in the latter case (eg. use
'$' PE_NAME to mean the hardcoded in case of conflict).


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