From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752829AbaGBJGr (ORCPT ); Wed, 2 Jul 2014 05:06:47 -0400 Received: from casper.infradead.org ([85.118.1.10]:59507 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751815AbaGBJGp (ORCPT ); Wed, 2 Jul 2014 05:06:45 -0400 Date: Wed, 2 Jul 2014 11:06:38 +0200 From: Peter Zijlstra To: "Yan, Zheng" Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, acme@infradead.org, eranian@google.com, andi@firstfloor.org Subject: Re: [PATCH V4 03/16] perf, x86: use context switch callback to flush LBR stack Message-ID: <20140702090638.GU6758@twins.programming.kicks-ass.net> References: <1404118253-19532-1-git-send-email-zheng.z.yan@intel.com> <1404118253-19532-4-git-send-email-zheng.z.yan@intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="onwk0SivC/dtQkFp" Content-Disposition: inline In-Reply-To: <1404118253-19532-4-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 --onwk0SivC/dtQkFp Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jun 30, 2014 at 04:50:40PM +0800, Yan, Zheng wrote: > @@ -185,6 +185,23 @@ void intel_pmu_lbr_enable(struct perf_event *event) > return; > =20 > /* > + * It is necessary to flush the stack on context switch. This happens > + * when the branch stack does not tag its entries with the pid of the > + * current task. Did you mean to say: "This happens _because_ the branch stack does not tag its entries with the pid of the current task." ? > + */ > + if (sched_in) { > + intel_pmu_lbr_reset(); > + cpuc->lbr_context =3D ctx; > + } > +} --onwk0SivC/dtQkFp Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJTs8udAAoJEHZH4aRLwOS6/3EP/iPj0TAmtUaTX0x5er6rR/wh dn4STUQkrzZwO66v5nN84EXVgYiblTHrIR+hFp2z8HbtJVOScdzaAFfUZ0CLsm8+ ndcX6RNQPqwVb+iHwmYzdOJTjv0AAl28g1eUslGk2OzyfhJv2BzWuwJz3BYs18qu YjciD8Xv7/Pmj15adIQawWe60rM8qe+f79iELdkYTzwjqCUhBXJpSgQ13BVyP518 uLMVFz1+ZwPDLeTHOABgTY+V7KDPiC3So5twDZg5A8yfpc5GRoeKhtfHBJfMh/qd GmcjhyLxXcz9Z5wVnqlqS6hkUYkQpVK0u4c9VLyiRGMATp3ariruMTmZHw0OUB0L 1e+x+nwa8R5zr4SucvhE64f/7PGlKC+H/Yn20OO2q2sO9eAHdLquso6n0kUf8hjd hnOMdm6waxly8Loytot1K3bQdrEOcnp0JzfkOna2uQRyoqhLQZNxNMtTnmu7/zru Yytw1p6u431CI4y7DC1sSvoxsBvwt/IrwfDPcmCBJMMfVOk4nnRteYv2uNsjeJrV 2OVvF4GZVjnEK1R+qTeOKDKs4igzECKhrK9KSYAs8bFxWlJoLMPpdHZKJm9UMxnX GWjBkVk+2PPDrrM2tUXm8/VZTMMPy27EGhV3wwpsIHF2e72gxr+F+YiVBY6FqIsu 8UoOeWcPeoaekjouTylh =oO4y -----END PGP SIGNATURE----- --onwk0SivC/dtQkFp--