From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755290Ab0C1Vxu (ORCPT ); Sun, 28 Mar 2010 17:53:50 -0400 Received: from smtp-out.google.com ([216.239.44.51]:35570 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752844Ab0C1Vxt (ORCPT ); Sun, 28 Mar 2010 17:53:49 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=mime-version:in-reply-to:references:date:message-id:subject:from:to: cc:content-type:x-system-of-record; b=fb88F84Ycf055njTJpPSP9e6EDOTAPoiSlqGI/r1Gw3txhvLVU9O0fEiGaHvr3RLd bSabteflg6CBzv7aH4NIA== MIME-Version: 1.0 In-Reply-To: <87aattpi90.fsf@basil.nowhere.org> References: <1269608924.12097.147.camel@laptop> <87aattpi90.fsf@basil.nowhere.org> Date: Sun, 28 Mar 2010 22:53:42 +0100 Message-ID: Subject: Re: [PATCH] perf, x86: Add Nehelem PMU programming errata workaround From: Stephane Eranian To: Andi Kleen Cc: Peter Zijlstra , Ingo Molnar , LKML Content-Type: text/plain; charset=UTF-8 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Mar 27, 2010 at 10:27 PM, Andi Kleen wrote: > Peter Zijlstra writes: > >> Subject: perf, x86: Add Nehelem PMU programming errata workaround >> From: Peter Zijlstra >> Date: Fri Mar 26 13:59:41 CET 2010 >> >> Implement the workaround for Intel Errata AAK100 and AAP53. >> >> Also, remove the Core-i7 name for Nehalem events since there are also >> Westmere based i7 chips. > > Did you actually see this happen? > This is the same as AAJ91. At the time, I created a test program and it was moderately easy to reproduce. > It looks like this will make the context switch into a perf > enabled process _MUCH_ more expensive, MSR writes are very slow. > Yes, but there is no alternative, I suspect.