Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754453AbZD2MjP (ORCPT ); Wed, 29 Apr 2009 08:39:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752654AbZD2Mi6 (ORCPT ); Wed, 29 Apr 2009 08:38:58 -0400 Received: from bilbo.ozlabs.org ([203.10.76.25]:50720 "EHLO bilbo.ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750918AbZD2Mi6 (ORCPT ); Wed, 29 Apr 2009 08:38:58 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <18936.18732.35199.647196@cargo.ozlabs.ibm.com> Date: Wed, 29 Apr 2009 22:33:48 +1000 From: Paul Mackerras To: Ingo Molnar Cc: Peter Zijlstra , Robert Richter , LKML Subject: Re: [PATCH 04/29] x86/perfcounters: rework pmc_amd_save_disable_all() and pmc_amd_restore_all() In-Reply-To: <20090429111159.GJ2373@elte.hu> References: <1241002046-8832-1-git-send-email-robert.richter@amd.com> <1241002046-8832-5-git-send-email-robert.richter@amd.com> <1241003260.8021.236.camel@laptop> <20090429111159.GJ2373@elte.hu> X-Mailer: VM 8.0.12 under 22.2.1 (i486-pc-linux-gnu) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 846 Lines: 21 Ingo Molnar wrote: > Could we remove the disable-all facility altogether and make the > core code NMI-safe? The current approach wont scale on CPUs that > dont have global-disable features. > > disable-all was arguably a hack i introduced and which spread too > far. Can you see a conceptual need for it? If you're talking about hw_perf_save_disable / hw_perf_restore, please don't get rid of those. I use them to batch up counter enable/disable operations so I only have to compute the PMU config once for each batch rather than every time an individual counter is enabled or disabled. Paul. -- 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/