From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753242Ab1LTKUp (ORCPT ); Tue, 20 Dec 2011 05:20:45 -0500 Received: from mx2.parallels.com ([64.131.90.16]:34791 "EHLO mx2.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752053Ab1LTKUi (ORCPT ); Tue, 20 Dec 2011 05:20:38 -0500 Message-ID: <4EF0614A.9020402@parallels.com> Date: Tue, 20 Dec 2011 14:19:54 +0400 From: Glauber Costa User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0) Gecko/20110927 Thunderbird/7.0 MIME-Version: 1.0 To: Peter Zijlstra CC: Martin Schwidefsky , Ingo Molnar , Stephen Rothwell , Thomas Gleixner , "H. Peter Anvin" , , Subject: Re: linux-next: manual merge of the tip tree with the cputime tree References: <20111219154010.c2044c038a6174dd8fb6f477@canb.auug.org.au> <20111219080813.GB30432@elte.hu> <20111219101134.3c2c0db5@de.ibm.com> <20111219103513.GA17928@elte.hu> <20111219133151.4d14af80@de.ibm.com> <1324303723.24621.1.camel@twins> In-Reply-To: <1324303723.24621.1.camel@twins> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/19/2011 06:08 PM, Peter Zijlstra wrote: > On Mon, 2011-12-19 at 13:31 +0100, Martin Schwidefsky wrote: >> Just one question: are you sure that you want the cpustat array >> to be u64 instead of cputime64_t? The content of the cpustat array is defined >> by the architecture semantics of cputime64_t, for CONFIG_VIRT_CPU_ACCOUNTING=y >> this is not a jiffy counter. If the array is u64 we won't get the sparse >> checking when reading from cpustat. > > So as Glauber said the reason was that we wanted to use simply > operators, and IIRC he wanted to add a few fields that had to be u64. > > I'm not sure what the current plans are wrt adding more fields, but with > your work cputime_t should again be a simple type and thus regular math > operators should work again, right? > > Glauber, do you still need to add fields? Due to the current state of discussions of cpu vs cpuacct, I think the final state of this is quite unclear. However, I think Martin's work is a quite worthwhile piece for us to have. So last case we can add extra fields in a different array and tell them apart by the index, etc. It shouldn't be expensive at all. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glauber Costa Subject: Re: linux-next: manual merge of the tip tree with the cputime tree Date: Tue, 20 Dec 2011 14:19:54 +0400 Message-ID: <4EF0614A.9020402@parallels.com> References: <20111219154010.c2044c038a6174dd8fb6f477@canb.auug.org.au> <20111219080813.GB30432@elte.hu> <20111219101134.3c2c0db5@de.ibm.com> <20111219103513.GA17928@elte.hu> <20111219133151.4d14af80@de.ibm.com> <1324303723.24621.1.camel@twins> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx2.parallels.com ([64.131.90.16]:34791 "EHLO mx2.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752053Ab1LTKUi (ORCPT ); Tue, 20 Dec 2011 05:20:38 -0500 In-Reply-To: <1324303723.24621.1.camel@twins> Sender: linux-next-owner@vger.kernel.org List-ID: To: Peter Zijlstra Cc: Martin Schwidefsky , Ingo Molnar , Stephen Rothwell , Thomas Gleixner , "H. Peter Anvin" , linux-next@vger.kernel.org, linux-kernel@vger.kernel.org On 12/19/2011 06:08 PM, Peter Zijlstra wrote: > On Mon, 2011-12-19 at 13:31 +0100, Martin Schwidefsky wrote: >> Just one question: are you sure that you want the cpustat array >> to be u64 instead of cputime64_t? The content of the cpustat array is defined >> by the architecture semantics of cputime64_t, for CONFIG_VIRT_CPU_ACCOUNTING=y >> this is not a jiffy counter. If the array is u64 we won't get the sparse >> checking when reading from cpustat. > > So as Glauber said the reason was that we wanted to use simply > operators, and IIRC he wanted to add a few fields that had to be u64. > > I'm not sure what the current plans are wrt adding more fields, but with > your work cputime_t should again be a simple type and thus regular math > operators should work again, right? > > Glauber, do you still need to add fields? Due to the current state of discussions of cpu vs cpuacct, I think the final state of this is quite unclear. However, I think Martin's work is a quite worthwhile piece for us to have. So last case we can add extra fields in a different array and tell them apart by the index, etc. It shouldn't be expensive at all.