svn commit: r363188 - in head: lib/libpmc sys/dev/hwpmc

[John Baldwin]

On 7/14/20 11:11 AM, Alexander Motin wrote:
> Author: mav
> Date: Tue Jul 14 18:11:05 2020
> New Revision: 363188
> URL: https://svnweb.freebsd.org/changeset/base/363188
> 
> Log:
>   Add stepping to the kern.hwpmc.cpuid string on x86.
>   
>   It follows the equivalent Linux change to be able to differentiate
>   skylakex and cascadelakex, sharing the same model but not stepping.
>   
>   This fixes skylakex handling broken by r363144.

Unfortunately this breaks compatibility meaning you can't use an older
libpmc with a newer kernel module after this change.  Perhaps we don't
consider libpmc stable, but this was really annoying as I booted a test
kernel today on an older Haswell box whose world is from before this
change and pmc doesn't work at all.  (pmccontrol -L doesn't list any
valid counters as the older libpmc presumably chokes on the additional
suffix and doesn't match anything)

-- 
John Baldwin