From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932256AbaIIIop (ORCPT ); Tue, 9 Sep 2014 04:44:45 -0400 Received: from casper.infradead.org ([85.118.1.10]:43470 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932206AbaIIIom (ORCPT ); Tue, 9 Sep 2014 04:44:42 -0400 Date: Tue, 9 Sep 2014 10:44:36 +0200 From: Peter Zijlstra To: Alexander Shishkin Cc: Ingo Molnar , linux-kernel@vger.kernel.org, Robert Richter , Frederic Weisbecker , Mike Galbraith , Paul Mackerras , Stephane Eranian , Andi Kleen , kan.liang@intel.com Subject: Re: [PATCH v4 09/22] perf: Support overwrite mode for AUX area Message-ID: <20140909084436.GY19379@twins.programming.kicks-ass.net> References: <1408538179-792-1-git-send-email-alexander.shishkin@linux.intel.com> <1408538179-792-10-git-send-email-alexander.shishkin@linux.intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="tsXbTCuc02oUSrD/" Content-Disposition: inline In-Reply-To: <1408538179-792-10-git-send-email-alexander.shishkin@linux.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 --tsXbTCuc02oUSrD/ Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Aug 20, 2014 at 03:36:06PM +0300, Alexander Shishkin wrote: > diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c > index 925f369947..5006caba63 100644 > --- a/kernel/events/ring_buffer.c > +++ b/kernel/events/ring_buffer.c > @@ -294,9 +295,22 @@ void perf_aux_output_end(struct perf_output_handle *= handle, unsigned long size, > bool truncated) > { > struct ring_buffer *rb =3D handle->rb; > + unsigned long aux_head; > =20 > + aux_head =3D local_read(&rb->aux_head); > + > + if (rb->aux_overwrite) { > + local_set(&rb->aux_head, size); > + > + /* > + * Send a RECORD_AUX with size=3D=3D0 to communicate aux_head > + * of this snapshot to userspace > + */ > + perf_event_aux_event(handle->event, size, 0, truncated); Humm.. why not write a 'normal' AUX record? Also, you didn't mention this in your Changelog _at_all_. > + } else { > + local_add(size, &rb->aux_head); > + perf_event_aux_event(handle->event, aux_head, size, truncated); > + } > =20 > smp_wmb(); > rb->user_page->aux_head =3D local_read(&rb->aux_head); --tsXbTCuc02oUSrD/ Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJUDr30AAoJEHZH4aRLwOS6lCoP/jQb5UxVEJ32Xoull2/DSlVw ZMBnlDwbW+ti3DlPIadaN3Te9bfUvH9f8B6X8NWz20kzwiX5cUIfDVKdBidwpRux Mf3wF4ur3zkdg5s/eGy3qTP3eFQPC54Gcs6onfnunJjJlWKf0kxTb1SiVHamdYnc yXegp/0qKIFnYjng+7mxw1HWAl7doetlzNYlNH43MfjMfi96X7ZympYLn7BpzMId DILl5buu9sb+06tKLvIDf1VKuOq7yB3sEn1m3qky3b5IOAfmGM87HdEFG5ej++xX BIQ7dj2nZnGKZwmGPWx28xPxVCdjd5y6JiRx43TUY7T3av11ZlWNIP0rZBq/lFWo 6XFgU9tgv9NBIzJdOuQVAz1IVR/htk/xcc4aOpjNAVphaifTiAH6WnQ8hwxNLRBr ZV0rKq9VycoInY0rn1d4b+n5Jp9LHBkVgtOr+KC7Dv5n2Xn6x/3mlIix2Knzsq6y CWjYgFWCTbw8QGZLIChVzuYpmmDvKGvjPnnLztsR2j7AbxnhNINiaYY3PbvcZ9Dc LtAB2hLE0MW/dHjyr8p8IBNkc2dTIS9YsTureElao9JzEvA+YI4sxo8UFYXrWoXm lc7Z8VWtAIIw8WnIR7A0hPzFs7oDnW09KrDqgfVoVoWWN/Sdy+OlmtZ92dEvsel7 N4PJB7zkSTy9h9R6XC66 =U0qA -----END PGP SIGNATURE----- --tsXbTCuc02oUSrD/--