Re: [PATCH v4 2/2] perf x86: Exposing an Uncore unit to PMON for Intel Xeon® server platform

From: Greg KH
Date: Fri Jan 17 2020 - 11:54:11 EST


On Fri, Jan 17, 2020 at 08:23:57AM -0800, Andi Kleen wrote:
> > I thought I was nice and gentle last time and said that this was a
> > really bad idea and you would fix it up. That didn't happen, so I am
> > being explicit here, THIS IS NOT AN ACCEPTABLE FILE OUTPUT FOR A SYSFS
> > FILE.
>
> Could you suggest how such a 1:N mapping should be expressed instead in
> sysfs?

I have yet to figure out what it is you all are trying to express here
given a lack of Documentation/ABI/ file :)

But again, sysfs is ONE VALUE PER FILE. You have a list of items here,
that is bounded only by the number of devices in the system at the
moment. That number will go up in time, as we all know. So this is
just not going to work at all as-is.

greg k-h