Re: [PATCH 2/7] perf: Create a symlink for a PMU

[Andi Kleen]

On 6/27/2021 11:55 PM, Greg KH wrote:
> On Sun, Jun 27, 2021 at 09:30:53AM -0700, Andi Kleen wrote:
> > > Then do not break things by renaming the device name, as you all have
> > > now stated that this name is part of the user/kernel api.
> > The renaming comes from the fallback mode on future systems. In the fallback
> > mode the driver doesn't know the true name, so it has to use  the numeric
> > name. If you don't use the fallback mode and have the full driver then yes
> > you'll get the same names as always (or at least as they make sense for the
> > hardware).
> >
> > But we would like to have the fallback mode too to allow more people use
> > uncore monitoring, and that's where the need to for the second name comes
> > in.
> So then just always use the "fallback" name if that is going to be the
> name you have for this hardware device.  Why would you want it to be
> renamed later on to a "fancier" name if there is only going to be
> one-per-chipset-type anyway?

It's an ugly numeric name, difficult to use

perf stat -e uncore_0_2//

instead of

perf stat -e uncore_cha//

It wouldn't exactly be an improvement for the full driver.

-Andi