Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755192AbZCEKIS (ORCPT ); Thu, 5 Mar 2009 05:08:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752993AbZCEKIH (ORCPT ); Thu, 5 Mar 2009 05:08:07 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:56258 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752826AbZCEKIF (ORCPT ); Thu, 5 Mar 2009 05:08:05 -0500 Date: Thu, 5 Mar 2009 11:07:48 +0100 From: Ingo Molnar To: Paul Mackerras Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Peter Zijlstra Subject: Re: [RFC PATCH] perfcounters: provide expansion room in the ABI Message-ID: <20090305100748.GB29499@elte.hu> References: <18862.19599.929591.3109@cargo.ozlabs.ibm.com> <20090304104945.GB4879@elte.hu> <18863.1197.527693.75146@drongo.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <18863.1197.527693.75146@drongo.ozlabs.ibm.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1462 Lines: 43 * Paul Mackerras wrote: > Ingo Molnar wrote: > > > > git://git.kernel.org/pub/scm/linux/kernel/git/paulus/perfcounters.git rfc > > > > > > include/linux/perf_counter.h | 12 +++++++++--- > > > include/linux/syscalls.h | 2 +- > > > kernel/perf_counter.c | 10 +++++++--- > > > 3 files changed, 17 insertions(+), 7 deletions(-) > > > > Pulled into tip:perfcounters/core, thanks Paul! > > Actually, I goofed slightly. In this bit of the patch: > > @@ -80,10 +81,15 @@ struct perf_counter_hw_event { > exclude_user : 1, /* don't count user */ > exclude_kernel : 1, /* ditto kernel */ > exclude_hv : 1, /* ditto hypervisor */ > + exclude_idle : 1, /* don't count when idle */ > > - __reserved_1 : 23; > + __reserved_1 : 55; > + > > the 55 should have been 54 if we want those bitfields to > occupy 64 bits. With 55 there, __reserved_1 will go in the > next 64-bit quadword (x86-speak, or doubleword in > powerpc-speak). > > Do you think that's worth changing? If so I'll do a commit > changing the 55 to 54. How about extending it to 118 instead? The creation of a counter is a slow path in any case. Ingo -- 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/