From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: [BUG] overflow in net/ipv4/route.c rt_check_expire() Date: Sat, 02 Apr 2005 16:10:10 +0200 Message-ID: <424EA7C2.6060308@cosmosbay.com> References: <424E641A.1020609@cosmosbay.com> <16974.41648.568927.54429@robur.slu.se> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable Cc: Herbert Xu , davem@davemloft.net, netdev@oss.sgi.com Return-path: To: Robert Olsson In-Reply-To: <16974.41648.568927.54429@robur.slu.se> Sender: netdev-bounce@oss.sgi.com Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org Robert Olsson a =E9crit : > Eric Dumazet writes: > Yes thats a pretty much load. Very short flows some reason? Well... yes. This is a real server, not a DOS simulation. 1 million TCP flows, and about 3 million peers using UDP frames. > What's your ip_rt_gc_min_interval? GC should be allowed to=20 > run frequent to smoothen out the GC load. Also good idea=20 > to decrease gc_thresh and you hash is really huge. No. As soon as I lower gc_thresh (and let gc running), the machine starts= to drop connections and crash some seconds later. I found I had to make the hash table very large (but lowering elasticity,= ie chain length) . It needs lot of ram, but at least CPU usage of net/ipv4/route.c is close = to 0. # grep . /proc/sys/net/ipv4/route/* /proc/sys/net/ipv4/route/error_burst:5000 /proc/sys/net/ipv4/route/error_cost:1000 /proc/sys/net/ipv4/route/gc_elasticity:2 /proc/sys/net/ipv4/route/gc_interval:1 /proc/sys/net/ipv4/route/gc_min_interval:0 /proc/sys/net/ipv4/route/gc_min_interval_ms:500 /proc/sys/net/ipv4/route/gc_thresh:2900000 /proc/sys/net/ipv4/route/gc_timeout:155 /proc/sys/net/ipv4/route/max_delay:10 /proc/sys/net/ipv4/route/max_size:16777216 /proc/sys/net/ipv4/route/min_adv_mss:256 /proc/sys/net/ipv4/route/min_delay:2 /proc/sys/net/ipv4/route/min_pmtu:552 /proc/sys/net/ipv4/route/mtu_expires:600 /proc/sys/net/ipv4/route/redirect_load:20 /proc/sys/net/ipv4/route/redirect_number:9 /proc/sys/net/ipv4/route/redirect_silence:20480 /proc/sys/net/ipv4/route/secret_interval:36000