From mboxrd@z Thu Jan 1 00:00:00 1970 From: "David S. Miller" Subject: Re: Route cache performance under stress Date: Thu, 22 May 2003 17:55:59 -0700 (PDT) Sender: netdev-bounce@oss.sgi.com Message-ID: <20030522.175559.70205743.davem@redhat.com> References: <20030522.034058.71558626.davem@redhat.com> <20030522114438.GD2961@netnation.com> <1053608586.9475.60.camel@tux.rsn.bth.se> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: sim@netnation.com, netdev@oss.sgi.com, linux-net@vger.kernel.org, kuznet@ms2.inr.ac.ru Return-path: To: gandalf@wlug.westbo.se In-Reply-To: <1053608586.9475.60.camel@tux.rsn.bth.se> Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org From: Martin Josefsson Date: 22 May 2003 15:03:07 +0200 On Thu, 2003-05-22 at 13:44, Simon Kirby wrote: > Nice! I tested with 300,000 routing table entries and there is no > discernable difference in performance from having an empty table. > vmstat shows the same idle time as when the routing table is empty. How much memory does a table that large use? 300,000 * sizeof(struct fib_node) the second term is: (2 * sizeof_pointer_on_this_architecture) + /* 8 or 16 bytes */ sizeof(u32) + /* 4 bytes */ 4 * sizeof(u8)) /* 4 bytes */ So that's 16 bytes on 32-bit systems, and 24 bytes on 64-bit systems. Therefore 300,000 routes take up 4.8MB on 32-bit systems and 7.2MB on 64-bit ones. I cannot fathom a way to make these any smaller :-)