Re: perf: Support uncore in 4.9.112

[Andi Kleen <ak@linux.intel.com>]

On Wed, Jul 18, 2018 at 11:29:50AM +0200, Greg KH wrote:
> On Wed, Jul 18, 2018 at 08:41:28AM +0800, Jin, Yao wrote:
> > Hi,
> > 
> > The stable kernel 4.9.112 has supported Intel uncore feature in perf core.
> > While it also needs the perf tool supporting to let perf uncore feature
> > work.
> > 
> > Following backport patches enables basic perf uncore feature in 4.9.112.
> > 
> > For example, on skylake desktop,
> 
> Why would anyone care about this on a "desktop" for 4.9?  No one should
> be using 4.9.y on a desktop anymore, it's over 2 years old, why would
> they expect any "new" hardware support to work for them?  Why can't they

It's actually not new hardware support: Skylake is fairly old hardware
at this point.

> just use 4.14.y or better yet. 4.17.y?  Desktops should NOT be using a 2
> year old kernel.
> 
> Heck, servers shouldn't either, but that's a totally different rant.

These chips are not only used in desktops but also in servers.

> However, for hardware that is newer than the base kernel version
> release, I have no sympathy.  Just use a newer kernel, right?

We have customers which are on old kernels with new hardware. 
The backports happen either way. This is just an attempt to do it in a
coordinated fashion.

> What distro relies on a 4.9 kernel for brand new hardware that does not
> already support a newer kernel release for such hardware?

None afaik, but there is a lot of Linux use beyond distros.

-Andi