Re: [PATCH] x86/topology: Fallback to SMT level only once

From: Peter Zijlstra
Date: Mon Aug 29 2016 - 06:40:57 EST

On Sun, Aug 28, 2016 at 08:19:46PM +0200, Jiri Olsa wrote:
> Jirka, Peter and Jean-Pierre reported performance drop on
> some cpus after making cpu offline and online again.
> The reason is the kernel logic that falls back to SMT
> level topology if more than one node is detected within
> CPU package. During the system boot this logic cuts out
> the DIE topology level and numa code adds NUMA level
> on top of this.

Its not SMT topology, and back when I asked if he had CoD enabled or
such he said not.

See also:

Arguably, that should have been split in two patches, but alas..