From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754155AbaE1H7y (ORCPT ); Wed, 28 May 2014 03:59:54 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:38374 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750912AbaE1H7w (ORCPT ); Wed, 28 May 2014 03:59:52 -0400 Date: Wed, 28 May 2014 09:59:37 +0200 From: Peter Zijlstra To: "Yan, Zheng" Cc: linux-kernel@vger.kernel.org, mingo@elte.hu, eranian@google.com, ak@linux.intel.com Subject: Re: [RFC PATCH 5/7] perf, x86: use the PEBS auto reload mechanism when possible Message-ID: <20140528075937.GO11096@twins.programming.kicks-ass.net> References: <1401257890-30535-1-git-send-email-zheng.z.yan@intel.com> <1401257890-30535-6-git-send-email-zheng.z.yan@intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="UaIp6+ubhcbWp687" Content-Disposition: inline In-Reply-To: <1401257890-30535-6-git-send-email-zheng.z.yan@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 --UaIp6+ubhcbWp687 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, May 28, 2014 at 02:18:08PM +0800, Yan, Zheng wrote: > When a fixed period is specified, this patch make perf use the PEBS > auto reload mechanism. This makes normal profiling faster, because > it avoids one costly MSR write in the PMI handler. >=20 You can't do this unconditionally. Like I think you mention in the next patch, we need the PMI to fix up lots of cases. --UaIp6+ubhcbWp687 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJThZdpAAoJEHZH4aRLwOS6ChAQAKlRuAJ3RQ1ho/GVP2D5fMGP YGws2lfQVYqeNPhxc92GXFyn9BKQIF4IerbAOqG9fGKIJWaRwDq9gby1uk+thgve ky6n6LN18Xt/mflNZPpHts9o9o9HJZgIKrzowttHaVWBK1MlBJ0Qiz4ZdBBRVjWE vadnqxHSBxrlaHtIXU2cNx3/tUeIidBqPmmBi7qbLewdb2JGleVP7pDvvRdGBIIl wEnXaMSO3pDEsvqEQEQi+bxR0eikVoDF9kzytODVewRoXvge8OZQZ8lkgTX3eC7a xeSZC5p3Z7CenFJhqrmULLsjbCUC8ErL+q23mmzKPtcpjiDQaZvGr4oN+XM7Aqga ASulAZp2somM0FFpVURebBlKMD4R5lR4plsQA3Khs8auQQfBvdVK/dLVxb+Sz4Iw 0U41Nh9nnMYjLXwv4oXXpkEz/4jK4EwwOj+6XqX22ukxABtFGXkBX64uANzyyn4m Y41tDpNtdk1pH4XNqfnoKMZZYJFuA1bDvaWsVDclatAnixqDi0LRfO4e59nRfT/z N+qURmxjDgHGjLMiQFwOEyX3XccxTd+GXyRg50S0YgRKMjvKg5/JOkDEKn9xLxqo +pEO6Mgp7MerFevOoAk43r3/R78lHmx6JY2JOC0cnOLRY7heU3pgSBIuTAoDy+6F mcIBLPLZFl9we2agPc52 =jfST -----END PGP SIGNATURE----- --UaIp6+ubhcbWp687--