From mboxrd@z Thu Jan 1 00:00:00 1970 From: arno@natisbad.org (Arnaud Ebalard) Subject: Re: [BUG,REGRESSION?] 3.11.6+,3.12: GbE iface rate drops to few KB/s Date: Thu, 21 Nov 2013 22:51:09 +0100 Message-ID: <871u298lv6.fsf@natisbad.org> References: <1384710098.8604.58.camel@edumazet-glaptop2.roam.corp.google.com> <87li0kkhzx.fsf@natisbad.org> <1384869194.8604.92.camel@edumazet-glaptop2.roam.corp.google.com> <20131119174323.GH913@1wt.eu> <1384885910.8604.110.camel@edumazet-glaptop2.roam.corp.google.com> <20131119184121.GN913@1wt.eu> <874n780wzc.fsf@natisbad.org> <20131120191145.GP8581@1wt.eu> <87txf692zx.fsf@natisbad.org> <20131120215435.GT8581@1wt.eu> <20131121004430.GX8581@1wt.eu> Mime-Version: 1.0 Content-Type: text/plain Cc: Thomas Petazzoni , Florian Fainelli , simon.guinot@sequanux.org, Eric Dumazet , netdev@vger.kernel.org, edumazet@google.com, Cong Wang , linux-arm-kernel@lists.infradead.org To: Willy Tarreau Return-path: Received: from smtp6-g21.free.fr ([212.27.42.6]:59240 "EHLO smtp6-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754106Ab3KUVvk (ORCPT ); Thu, 21 Nov 2013 16:51:40 -0500 Received: from smtp.natisbad.org (unknown [IPv6:2a01:e35:139b:9f90:221:70ff:fe55:8f78]) by smtp6-g21.free.fr (Postfix) with ESMTP id 751D3822B0 for ; Thu, 21 Nov 2013 22:51:25 +0100 (CET) Sender: netdev-owner@vger.kernel.org List-ID: Hi, Willy Tarreau writes: > OK it paid off. And very well :-) > > I did it at once and it worked immediately. I generally don't like this > because I always fear that some bug was left there hidden in the code. I have > only tested it on the Mirabox, so I'll have to try on the OpenBlocks AX3-4 and > on the XP-GP board for some SMP stress tests. > > I upgraded my Mirabox to latest Linus' git (commit 5527d151) and compared > with and without the patch. > > without : > - need at least 12 streams to reach gigabit. > - 60% of idle CPU remains at 1 Gbps > - HTTP connection rate on empty objects is 9950 connections/s > - cumulated outgoing traffic on two ports reaches 1.3 Gbps > > with the patch : > - a single stream easily saturates the gigabit > - 87% of idle CPU at 1 Gbps (12 streams, 90% idle at 1 stream) > - HTTP connection rate on empty objects is 10250 connections/s > - I saturate the two gig ports at 99% CPU, so 2 Gbps sustained output. > > BTW I must say I was impressed to see that big an improvement in CPU > usage between 3.10 and 3.13, I suspect some of the Tx queue improvements > that Eric has done in between account for this. > > I cut the patch in 3 parts : > - one which reintroduces the hidden bits of the driver > - one which replaces the timer with the IRQ > - one which changes the default Tx coalesce from 16 to 4 packets > (larger was preferred with the timer, but less is better now). > > I'm attaching them, please test them on your device. Well, on the RN102 (Armada 370), I get the same results as with your previous patch, i.e. netperf and nginx saturate the link. Apache still lagging behind though. > Note that this is *not* for inclusion at the moment as it has not been > tested on the SMP CPUs. I tested it on my RN2120 (2-core armada XP): I got no problem and the link saturated w/ apache, nginx and netperf. Good work! Cheers, a+