From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH] NET : convert network timestamps to ktime_t Date: Fri, 2 Mar 2007 08:27:23 -0800 Message-ID: <20070302082723.7105b0c1@oldman> References: <45E5570E.7050301@free.fr> <200703011230.50596.dada1@cosmosbay.com> <45E6F744.8070106@linux-foundation.org> <200703021538.41284.dada1@cosmosbay.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: David Miller , John find , netdev@vger.kernel.org To: Eric Dumazet Return-path: Received: from smtp.osdl.org ([65.172.181.24]:33854 "EHLO smtp.osdl.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992583AbXCBQ2A (ORCPT ); Fri, 2 Mar 2007 11:28:00 -0500 In-Reply-To: <200703021538.41284.dada1@cosmosbay.com> Sender: netdev-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Fri, 2 Mar 2007 15:38:41 +0100 Eric Dumazet wrote: > We currently use a special structure (struct skb_timeval) and plain 'struct > timeval' to store packet timestamps in sk_buffs and struct sock. > > This has some drawbacks : > - Fixed resolution of micro second. > - Waste of space on 64bit platforms where sizeof(struct timeval)=16 > > I suggest using ktime_t that is a nice abstraction of high resolution time > services, currently capable of nanosecond resolution. > > As sizeof(ktime_t) is 8 bytes, using ktime_t in 'struct sock' permits a 8 byte > shrink of this structure on 64bit architectures. Some other structures also > benefit from this size reduction (struct ipq in ipv4/ip_fragment.c, struct > frag_queue in ipv6/reassembly.c, ...) This is even better. Also comparing ktime_t's is easier if some code needs to do that.