From mboxrd@z Thu Jan 1 00:00:00 1970 From: Octavian Purdila Subject: Re: [RFC][PATCH 1/1] net: support for hardware timestamping Date: Tue, 29 Jul 2008 19:11:10 +0300 Message-ID: <200807291911.10364.opurdila@ixiacom.com> References: <1217290080-4251-1-git-send-email-opurdila@ixiacom.com> <1217343163.30512.34.camel@ecld0pohly> <20080729085457.033a9fd2@extreme> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: Patrick Ohly , netdev@vger.kernel.org To: Stephen Hemminger Return-path: Received: from ixia01.ro.gtsce.net ([212.146.94.66]:20302 "EHLO ixro-ex1.ixiacom.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1750712AbYG2QNl (ORCPT ); Tue, 29 Jul 2008 12:13:41 -0400 In-Reply-To: <20080729085457.033a9fd2@extreme> Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: On Tuesday 29 July 2008, Stephen Hemminger wrote: > > In my sky2 sample code, I took a different approach: > 1. Why have HW timestamps different than existing timestamps? If you > just use existing timestamp, no socket API is needed. I agree that is a much better approach if you are ok with the variance introduced by synchronizing the HW timestamps with the CPU clock. But if you want to precisely measure one-way delays, and if you have the hw timestamp units synchronized across the nodes, then you need the hardware timesetamp. Or maybe I am stuck on this idea because of doing things this way for a long time and there is a better solution? Thanks, tavi