From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756881AbcH2Kky (ORCPT ); Mon, 29 Aug 2016 06:40:54 -0400 Received: from merlin.infradead.org ([205.233.59.134]:39524 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756125AbcH2Kkx (ORCPT ); Mon, 29 Aug 2016 06:40:53 -0400 Date: Mon, 29 Aug 2016 12:40:47 +0200 From: Peter Zijlstra To: Jiri Olsa Cc: Jean-Pierre Lozi , Jirka Hladky , Petr =?iso-8859-1?Q?Sur=FD?= , lkml , Ingo Molnar , Thomas Gleixner , "H. Peter Anvin" Subject: Re: [PATCH] x86/topology: Fallback to SMT level only once Message-ID: <20160829104047.GH10153@twins.programming.kicks-ass.net> References: <1472408386-5254-1-git-send-email-jolsa@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1472408386-5254-1-git-send-email-jolsa@kernel.org> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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..