Re: [PATCH v3 1/5] perf_event: introduce 'inject' event and get HZ

[Peter Zijlstra <peterz@infradead.org>]

On Wed, 2009-12-30 at 17:37 +0800, Xiao Guangrong wrote:
> > I really dislike the name, event injection to me would be like a write()
> > interface where you provide the actual event data to be stuffed in the
> > output stream.
> > 
> 
> Yes, it like write and it writes something form kernel to perf.
> And, i think this name is suitable for it's doing that injects an
> 'artificial' event, it's well if you have other name for it :-)

No, what I means is that you cannot actually inject an arbitrary event.
Sure it injects something, but that's pretty limited.

> > This just seems like a very weird way of getting data out. A kind of
> > like sysconf() but done very strange.
> > 
> 
> It's since some parameter is only used by perf, suce as HZ in this patch and
> 'relocation offset' in my other patchset, it also well if has better way to
> do it :-)

The thing is, this proposed interface is very much tied to perf and
makes it basically impossible for !perf to use. Whereas I can imagine
esp. the relocation offset to be interesting for other things. Basically
everything needing to resolve a kernel symbol.