From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [rfc] new sk_buff member: hwstamp Date: Mon, 14 Jul 2008 17:43:21 -0700 Message-ID: <20080714174321.30d6d62a@extreme> References: <200807141843.00845.opurdila@ixiacom.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Octavian Purdila Return-path: Received: from [216.93.170.194] ([216.93.170.194]:37633 "EHLO mail.vyatta.com" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754410AbYGOAna (ORCPT ); Mon, 14 Jul 2008 20:43:30 -0400 In-Reply-To: <200807141843.00845.opurdila@ixiacom.com> Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 14 Jul 2008 18:43:00 +0300 Octavian Purdila wrote: > > Hi everybody, > > In our Linux port we added a new sk_buff member, hwstamp, to store a hardware > generated timestamp for received packets. The hardware can also insert > hardware timestamps in the payload on the TX path and can have the RX / TX > clocks synchronized. We use this infrastructure to compute one-way delays > with high precision (20ns resolution). > > I know that adding new members to such heavily used structures like the skb is > viewed harshly - especially for such exotic cases as the one described above. > So, would such a patch be considered for inclusion? Or maybe there is a > better way of doing the above? > Why not do some clock synchronization and use existing absolute timestamp? This would benefit system generally since it would give more accurate values for network traffic analysis.