From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753999Ab1LMA0u (ORCPT ); Mon, 12 Dec 2011 19:26:50 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:56027 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753685Ab1LMA0t (ORCPT ); Mon, 12 Dec 2011 19:26:49 -0500 Message-ID: <4EE69BAB.9010302@fb.com> Date: Mon, 12 Dec 2011 16:26:19 -0800 From: Arun Sharma User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.7; rv:8.0) Gecko/20111105 Thunderbird/8.0 MIME-Version: 1.0 To: john stultz CC: , Kumar Sundararajan , Peter Zijlstra , Ingo Molnar , Thomas Gleixner , Andy Lutomirski Subject: Re: [PATCH 2/2] Add a thread cpu time implementation to vDSO References: <1323718578-1157-1-git-send-email-asharma@fb.com> <1323718578-1157-3-git-send-email-asharma@fb.com> <1323731361.4078.102.camel@work-vm> <4EE68C31.1030207@fb.com> <1323732772.4078.113.camel@work-vm> In-Reply-To: <1323732772.4078.113.camel@work-vm> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [192.168.18.252] X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.5.7110,1.0.211,0.0.0000 definitions=2011-12-12_10:2011-12-12,2011-12-12,1970-01-01 signatures=0 X-Proofpoint-Spam-Reason: safe Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/12/11 3:32 PM, john stultz wrote: > Is it just that you're concerned about the clockid switch costs being > too high? Yeah - but I have no real-world data to back it up (I don't think micro benchmarks are a good way to analyze this). clock_gettime_ns() may just be the right answer here. -Arun