Re: [PATCH v2 00/14] perf, persistent: Kernel updates for perf toolintegration

[Ingo Molnar]

* Borislav Petkov <bp@xxxxxxxxx> wrote:

> On Wed, Jun 26, 2013 at 10:12:23AM +0200, Robert Richter wrote:
> > We get a new fd by opening the persistent event with the syscall.
> > There would be 2 new ioctls:
> > 
> >  ioctl(fd, PERF_EVENT_IOC_DETACH, 0);
> >  ioctl(fd, PERF_EVENT_IOC_ATTACH, 0);
> > 
> > This would be fine and reuses existing infrastructure.
> 
> Well, how are you going to say that you want to open an already existing 
> persistent event or your want to create exactly the same persistent 
> event? Are we even going to allow identical persistent events to 
> coexist?

If already existing persistent events show up somewhere in sysfs (or in a 
separate pseudofilesystem) then an open() of them [given sufficient 
privileges of the caller, etc.] could attach to them.

Thanks,

	Ingo
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