From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Hutchings Subject: Re: TCPBacklogDrops during aggressive bursts of traffic Date: Tue, 15 May 2012 17:47:34 +0100 Message-ID: <1337100454.2544.25.camel@bwh-desktop.uk.solarflarecom.com> References: <1337092718.1689.45.camel@kjm-desktop.uk.level5networks.com> <1337093776.8512.1089.camel@edumazet-glaptop> <1337099368.1689.47.camel@kjm-desktop.uk.level5networks.com> <1337099641.8512.1102.camel@edumazet-glaptop> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: Kieran Mansley , To: Eric Dumazet Return-path: Received: from webmail.solarflare.com ([12.187.104.25]:16594 "EHLO ocex02.SolarFlarecom.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757470Ab2EOQri (ORCPT ); Tue, 15 May 2012 12:47:38 -0400 In-Reply-To: <1337099641.8512.1102.camel@edumazet-glaptop> Sender: netdev-owner@vger.kernel.org List-ID: On Tue, 2012-05-15 at 18:34 +0200, Eric Dumazet wrote: > On Tue, 2012-05-15 at 17:29 +0100, Kieran Mansley wrote: > > On Tue, 2012-05-15 at 16:56 +0200, Eric Dumazet wrote: > > > > > > Please try latest kernels, this is probably 'fixed' > > > > I've just tried with 3.4.0-rc7 and the problem is still reproducible. > > It's perhaps harder to reproduce than on 3.3.6 but still there. > > > > > What network driver are you using ? > > > > The receiver is using the sfc driver that is included in the kernel > > build, together with an SFC 9020 NIC. > > > > Kieran > > > > MTU ? 1500 > What is typical skb->truesize of skb given to stack in RX path ? > > If drivers use PAGE_SIZE fragments, then you are more likely to hit > limit. We're passing page fragments into GRO. Ben. -- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.