From mboxrd@z Thu Jan 1 00:00:00 1970 From: Denys Fedoryshchenko Subject: Re: REDIRECT in nat OUTPUT Date: Sun, 13 Jul 2008 17:19:50 +0300 Message-ID: <200807131719.50777.denys@visp.net.lb> References: <200807120424.56462.denys@visp.net.lb> <200807121740.25789.denys@visp.net.lb> <20080713140930.GA23238@2ka.mipt.ru> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, netfilter-devel@vger.kernel.org, David Miller , Eric Dumazet To: Evgeniy Polyakov Return-path: In-Reply-To: <20080713140930.GA23238@2ka.mipt.ru> Content-Disposition: inline Sender: netfilter-devel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Sunday 13 July 2008, Evgeniy Polyakov wrote: > On Sat, Jul 12, 2008 at 05:40:25PM +0300, Denys Fedoryshchenko (denys@visp.net.lb) wrote: > > Seems i found something. After issuing ethtool -K lo tso on i got significant performance improvement. > > Why it is not on by default? > > Without it performance is VERY poor. > > TSO over loopback turns to be GSO, which allows to aggregate multiple > packets into single frame. If system is not CPU bound, then it is likely > REDIRECT problem. If I understood you corerctly, loopback performance is > always good without REDIRECT, but fails to miserable level when > apprpriate rule is used? > No, seems it has performance issues without redirect(and conntrack unloaded too) even, iperf results on loopback is very unstable. Actually i dont understand, how on idle machine with Xeon processor iperf over loopback (tcp) can be ~100Mbps? I think it is a bug. -- ------ Technical Manager Virtual ISP S.A.L. Lebanon