Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758393AbaDIISh (ORCPT ); Wed, 9 Apr 2014 04:18:37 -0400 Received: from merlin.infradead.org ([205.233.59.134]:34789 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758366AbaDIISf (ORCPT ); Wed, 9 Apr 2014 04:18:35 -0400 Date: Wed, 9 Apr 2014 10:18:24 +0200 From: Peter Zijlstra To: "Brown, Len" Cc: Davidlohr Bueso , "mingo@kernel.org" , "hpa@zytor.com" , "linux-kernel@vger.kernel.org" , "tglx@linutronix.de" , "hpa@linux.intel.com" , "linux-tip-commits@vger.kernel.org" Subject: Re: [tip:x86/urgent] x86 idle: Repair large-server 50-watt idle-power regression Message-ID: <20140409081824.GZ10526@twins.programming.kicks-ass.net> References: <1395102010.2474.21.camel@buesod1.americas.hpqcorp.net> <1A7043D5F58CCB44A599DFD55ED4C94845CA12EC@fmsmsx115.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1A7043D5F58CCB44A599DFD55ED4C94845CA12EC@fmsmsx115.amr.corp.intel.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Apr 08, 2014 at 09:43:54PM +0000, Brown, Len wrote: > #1: skip flush for C1 > #2: skip flush for C1 and C1E One stray thought I had: IFF the erratum is due to the cache flushing of the higher C states, these two patches should still be correct while also (possibly) avoiding the performance penalty, since C1* doesn't flush caches yet. Of course, I've no clue if this is indeed the root cause of this particular erratum and I'm not sure you guys are allowed to say even if you would know :/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/