Messages in this thread | | | Date | Tue, 24 Jan 2012 16:53:42 -0800 | From | Greg KH <> | Subject | Re: [RFCv3 0/9] perf tool: parser generator for events parsing |
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On Tue, Jan 24, 2012 at 05:26:04PM +0100, Peter Zijlstra wrote: > On Mon, 2012-01-16 at 13:31 +0100, Jiri Olsa wrote: > > Here's new version of event parsing patchset. To summarize: > > - adding event parser bison/flex generator > > - the event syntax stays as it was > > - adding event format file sysfs attribute > > for pmu device > > Added Greg to CC, please also see: https://lkml.org/lkml/2012/1/16/148 > > Right, lets hope we can convince the sysfs people that a few lines are > ok.. if not we need to find another way to represent all this muck, one > alternative is exploding the whole thing into a sysfs hierarchy like: > > > format/event: config:0-7 > ... > > format/config: config:0-63 > format/config1: config1:0-63 > format/config2: config2:0-63 > > that will of course consume loads more resources but if that's what it > takes :-(
Well, what's to keep someone from exploding one of those files to go over the buffer size without knowing it?
Even after reading the above link, I can't really understand what this is being used for. As it's sysfs files, why aren't Documentation/ABI/ files also being created with the patch explaining it all?
Again, if at all possible, sysfs should be one value per file. Please NEVER create a sysfs file that requires a parser to determine what is going on in it. It should be a simple 'read the value' type thing.
So yes, multiple sysfs files do make sense, the resource load should be almost non-existant for new ones.
thanks,
greg k-h
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