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

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Message-ID: <20160829110926.GB32481@krava>
Date:   Mon, 29 Aug 2016 13:09:26 +0200
From:   Jiri Olsa <jolsa@...hat.com>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     Jiri Olsa <jolsa@...nel.org>, Jean-Pierre Lozi <jplozi@...ce.fr>,
        Jirka Hladky <jhladky@...hat.com>,
        Petr Surý <psury@...hat.com>,
        lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH] x86/topology: Fallback to SMT level only once

On Mon, Aug 29, 2016 at 12:40:47PM +0200, Peter Zijlstra wrote:
> 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:
> 
> http://lkml.kernel.org/r/1471559812-19967-3-git-send-email-srinivas.pandruvada@linux.intel.com
> 
> Arguably, that should have been split in two patches, but alas..

ok, that change will work for us as well

are you going to pull it?

thanks,
jirka