Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753481AbaGOOia (ORCPT ); Tue, 15 Jul 2014 10:38:30 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:58214 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751916AbaGOOh4 (ORCPT ); Tue, 15 Jul 2014 10:37:56 -0400 Date: Tue, 15 Jul 2014 16:37:45 +0200 From: Peter Zijlstra To: Vince Weaver Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Arnaldo Carvalho de Melo , Stephane Eranian Subject: Re: perf: FORMAT_GROUP on attached process stops working in 3.16-rc Message-ID: <20140715143745.GK9918@twins.programming.kicks-ass.net> References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="2KNN3gYh9MUZz6n4" Content-Disposition: inline In-Reply-To: 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 --2KNN3gYh9MUZz6n4 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jul 15, 2014 at 10:36:33AM -0400, Vince Weaver wrote: > Hello >=20 > I noticed in the 3.16-rc kernels that one of my regression tests was=20 > failing, specifically > https://github.com/deater/perf_event_tests/blob/master/tests/bugs/read_g= roup_attached.c >=20 > This test creates an event group with two events and PERF_FORMAT_GROUP > set. >=20 > It creates a child process, stops it, attaches the event group to it,=20 > starts the events and the child, waits for the child to finish, stops the > events, then reads the value. >=20 > In theory a subsequent read from the group leader should return values fo= r=20 > *both* events (due to PERF_FORMAT_GROUP) but this stopped working, it onl= y=20 > returns the value for the leader. >=20 > I've bisected it down to change: 15a2d4de0eab5=20 > "perf: Always destroy groups on exit" >=20 > So is this expected behavior due to this patch, or is it a regression? Regression, lemme try and wrap my head around it. Thanks! --2KNN3gYh9MUZz6n4 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJTxTy5AAoJEHZH4aRLwOS6NC0P/jpHgZIPIZzaJxJgrj2NNR0j mNjpMh4p5Qg8xxStXI1/gsip0cyr4SXwytEA/FxmmEg2hdKDqMb7ukSMCVLgy6wq py6RIq50ubzsEaXqQ6x3laRRf5BsleHCkprlgLuvTuLEnPRstUFovLXi4aej7ndy gOLO5e0FjJFnxq0mY7QJgjSCss6H3qIAiy0Qy/wiDhAjGXIwyH1u4R2uH7WGaog7 rU/+6OSNaJVRFQImGrvfdo2Q/Otz7O/8F2iErDlYz+msQTUUAYpT3+hrbZzYasvv 3k2SdOXTaFzUi0Z2h4HHkMuAht3gv8FghB1i+0ODoPDYj+WMNBR+bBALBiXTb0qe BsUIn3zZkMWX02l7YS2NUIcPRS/mwUqzTmHlu5xVV0vBbqkKEc+Z24VB9SI/ArTk 8Abq6m5Ah7P47RJWVviIKsscjf2azecVh++RMZd+8DZdNKr9QxmiWrtUYqtEPpya MPTBcqgpHDsAP97TGbOKRbWPO8AyrcKzRTvo7I3TpzgZ8DVKek4s6llP8GOQUVnK ZK4Mfp9kc6KuzO8mIFZYh9ePj1v0h/VqaqeUIzl+S9hZdT6hzyZm7p3VNDbiXK1q b/0TpFTliwJUb2x/6VLwXe5AI/JbQC1U2uvvAtTEPVKtjnvGeko8JyB+4CQxGv2B vRztpz8YL+IocAoJ7CBj =/O6A -----END PGP SIGNATURE----- --2KNN3gYh9MUZz6n4-- -- 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/