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

From: Jiri Olsa
Date: Wed Feb 15 2012 - 04:24:41 EST


On Tue, Feb 14, 2012 at 10:03:11PM +0100, Peter Zijlstra wrote:
> On Tue, 2012-02-14 at 21:57 +0100, Peter Zijlstra wrote:
> > On Tue, 2012-02-14 at 21:20 +0100, Peter Zijlstra wrote:
> > > OK, this one works. the attributes thing wants NULL termination.
> > > Thanks
> > > for mentioning that Jiri.
> >
> > OK, it mostly works, except:
> >
> > perf record -e "cpu/config=0x108000c0/upp" ./loop_1b_locks
> >
> > doesn't seem to work...
>
> This seems to come back to hardcoding config* vs including it in every
> single format description.
>
> I prefer to have all perf_event_attr fields (of interest) hard-coded in
> the parser so that we can omit them for all actual format descriptions.
>
> 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 ???)

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..

jirka
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