From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David S. Miller" Subject: Re: Route cache performance under stress Date: Tue, 10 Jun 2003 17:58:13 -0700 (PDT) Sender: netdev-bounce@oss.sgi.com Message-ID: <20030610.175813.74726237.davem@redhat.com> References: <20030610.165759.78731321.davem@redhat.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: Robert.Olsson@data.slu.se, hadi@shell.cyberus.ca, xerox@foonet.net, sim@netnation.com, fw@deneb.enyo.de, netdev@oss.sgi.com, linux-net@vger.kernel.org Return-path: To: ralph+d@istop.com, ralph@istop.com In-Reply-To: Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org From: Ralph Doncaster Date: Tue, 10 Jun 2003 20:41:13 -0400 (EDT) On Tue, 10 Jun 2003, David S. Miller wrote: > Guess you never run tcpdump nor use packet schedulers. So because some (in the case of a core router almost none) of the packets will need a timestamp, you do it for every single one of them? In order to be accurate, we must obtain the timestamp exactly when we receive the packet. But until we know that the packet is for us or not (which requires a route lookup), we don't know if we actually need the timestamp or not. This is not some arbitrary thing, this is how you have to implement this. It's not like we said "screw everyone, let's get a timestamp all the time whether we need it or not." :-)