From owner-freebsd-net@FreeBSD.ORG Sun May 12 20:07:19 2013 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id 188F067E for ; Sun, 12 May 2013 20:07:19 +0000 (UTC) (envelope-from scott4long@yahoo.com) Received: from nm5.bullet.mail.bf1.yahoo.com (nm5.bullet.mail.bf1.yahoo.com [98.139.212.164]) by mx1.freebsd.org (Postfix) with SMTP id BD47BCB9 for ; Sun, 12 May 2013 20:07:18 +0000 (UTC) Received: from [98.139.215.142] by nm5.bullet.mail.bf1.yahoo.com with NNFMP; 12 May 2013 20:07:12 -0000 Received: from [98.139.213.3] by tm13.bullet.mail.bf1.yahoo.com with NNFMP; 12 May 2013 20:07:12 -0000 Received: from [127.0.0.1] by smtp103.mail.bf1.yahoo.com with NNFMP; 12 May 2013 20:07:12 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.com; s=s1024; t=1368389232; bh=8cnjSct0A2fEeelDAsYYYYdV9ZYLAUU6urWY6ma1sSw=; h=X-Yahoo-Newman-Id:X-Yahoo-Newman-Property:X-YMail-OSG:X-Yahoo-SMTP:X-Rocket-Received:Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Cc:Content-Transfer-Encoding:Message-Id:References:To:X-Mailer; b=Dkss36bvIQ70ezFiKlVeJARiJ7eZRCXDfLPsG0PbgPPxtWKXB80VKhtvZnQolnsQP1tvKzteLkC8PG+gHIiSvmFsXbd3bcilkcMUAJX3QJOrH5qKzxV+jj/KdvdG2cm9p4EPV6Pm9WGakU8uXnHI+c2GssslhcliNhz7qENp4ng= X-Yahoo-Newman-Id: 486807.98641.bm@smtp103.mail.bf1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: kImT08MVM1k_d7ogQ.BQ8syxtMU_crY5RL3UzzcdqjIi4es N4T9x2mLjiQiRpElfTDsOJcdN_d45cDSUaZoyDnyuuy6CKlWGfHqWYvKpXMj my4hj0T9oEIFCuc18FCMt7uaL1hkHJNNX8_lEgzlpwWvinr_A2EvS9Goblcv nt1Y0uUx1kys6fAvrTbi.6NFWmyVF7jac2wDHGsLC.3qIT.kxfU6l_FeNwST NM0ScpLOYwz_8zpbaO.eZ7Gk.ZAJrOJgYKf7M6OzskrvI0_4JWJeKP7GaTv7 wukjywuSk5t2rC5jm1JPv_oXDN0HYp5Ewj1pExt3eN9NNcUPPBdfuHqURRFF H.ViT.eY4wJebQe3IKXzh_hqV9jCe6pgAdHG1Z_4vEffTzfL4GBWLwYpbd9j YXUi1D.dx_3ca9R3gC5WTHFOrgEs_W.Rsz.ihzTZAzwdDAGkSLY6tlSzZomD 1P67y__mM0M5hnA-- X-Yahoo-SMTP: clhABp.swBB7fs.LwIJpv3jkWgo2NU8- X-Rocket-Received: from [192.168.254.206] (scott4long@168.103.85.57 with ) by smtp103.mail.bf1.yahoo.com with SMTP; 12 May 2013 13:07:12 -0700 PDT Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 6.3 \(1503\)) Subject: Re: High CPU interrupt load on intel I350T4 with igb on 8.3 From: Scott Long In-Reply-To: <518EA643.5010505@gmail.com> Date: Sun, 12 May 2013 14:07:11 -0600 Content-Transfer-Encoding: quoted-printable Message-Id: <195AF945-C1C9-4EE8-9A8E-A196E4658184@yahoo.com> References: <1368287797.70288.YahooMailClassic@web121603.mail.ne1.yahoo.com> <518EA643.5010505@gmail.com> To: Hooman Fazaeli X-Mailer: Apple Mail (2.1503) Cc: freebsd-net@freebsd.org, =?iso-8859-1?Q?=22Cl=E9ment_Hermann_=28nodens=29=22?= , Eugene Grosbein X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 12 May 2013 20:07:19 -0000 On May 11, 2013, at 2:12 PM, Hooman Fazaeli = wrote: > On 5/11/2013 8:26 PM, Barney Cordoba wrote: >> Clearly you don't understand the problem. Your logic is that because = other drivers are defective also; therefore its not a driver problem? = The problem is caused by a multi-threaded driver that >> haphazardly launches tasks and that doesn't manage the case that the = rest of the system can't handle the load. It's no different than a = driver that barfs when mbuf clusters are exhausted. The answer >> isn't to increase memory or mbufs, even though that may alleviate the = problem. The answer is to fix the driver, so that it doesn't crash the = system for an event that is wholly predictable. igb has >> 1) too many locks and 2) exasperates the problem by binding to cpus, = which causes it to not only have to wait for the lock to free, but also = for a specific cpu to become free. So it chugs along >> happily until it encounters a bottleneck, at which point it quickly = blows up the entire system in a domino effect. It needs to manage locks = more efficiently, and also to detect when the backup is >> unmanageable. Ever since FreeBSD 5 the answer has been "it's fixed in = 7, or its fixed in 9, or it's fixed in 10". There will always be = bottlenecks, and no driver should blow up the system no matter >> what intermediate code may present a problem. Its the driver's = responsibility to behave and to drop packets if necessary. BC >=20 > And how the driver should behave? You suggest dropping the packets. = Even if we accept > that dropping packets is a good strategy in all configurations (which = I doubt), the driver is > definitely not the best place to implement it, since that involves = duplication of similar > code between drivers. Somewhere like the Ethernet layer is a much = better choice to watch > load of packets and drop them to prevent them to eat all the cores. = Furthermore, ignoring > the fact that pf is not optimized for multi-processors and blaming = drivers for not adjusting > themselves with the this pf's fault, is a bit unfair, I believe. >=20 Fortunately I no longer receive Barney's emails, but it still distresses = me to see him trolling the list. It should be a pretty big hint that Barney has nothing to offer the = conversation when he suggests on a technical level that dropping packets is an acceptable = policy for drivers. The conversation is also over when he resorts to the ad hominem attacks = and the blanket "driver X sucks and you all are too lazy to follow my brilliance = in fixing it" tripe. Can we all just put him on ignore and move on? A brief search of the PR = database shows no contributions from him. A brief search of the mailing lists = shows only inflamed diatribes and insults from him, with a brief smattering here = and there of benign but content-free posts. On the other hand, if the consensus here is to keep on baiting and = feeding him for our own amusement, I applaud the effort but ask for a bit more subtlety = =3D-) Thanks! Scott