From owner-freebsd-current@FreeBSD.ORG Thu Dec 1 20:09:50 2005 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 316A616A41F; Thu, 1 Dec 2005 20:09:50 +0000 (GMT) (envelope-from ambrisko@ambrisko.com) Received: from mail.ambrisko.com (mail.ambrisko.com [64.174.51.43]) by mx1.FreeBSD.org (Postfix) with ESMTP id BF25743D5A; Thu, 1 Dec 2005 20:09:49 +0000 (GMT) (envelope-from ambrisko@ambrisko.com) Received: from server2.ambrisko.com (HELO www.ambrisko.com) ([192.168.1.2]) by mail.ambrisko.com with ESMTP; 01 Dec 2005 12:09:49 -0800 Received: from ambrisko.com (localhost [127.0.0.1]) by www.ambrisko.com (8.12.11/8.12.9) with ESMTP id jB1K9nrw016309; Thu, 1 Dec 2005 12:09:49 -0800 (PST) (envelope-from ambrisko@ambrisko.com) Received: (from ambrisko@localhost) by ambrisko.com (8.12.11/8.12.11/Submit) id jB1K9nXq016308; Thu, 1 Dec 2005 12:09:49 -0800 (PST) (envelope-from ambrisko) From: Doug Ambrisko Message-Id: <200512012009.jB1K9nXq016308@ambrisko.com> In-Reply-To: <20051201200242.GA4197@xor.obsecurity.org> To: Kris Kennaway Date: Thu, 1 Dec 2005 12:09:49 -0800 (PST) X-Mailer: ELM [version 2.4ME+ PL94b (25)] MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII Cc: freebsd-current@freebsd.org, Darren Pilgrim Subject: Re: em interrupt storm X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 01 Dec 2005 20:09:50 -0000 Kris Kennaway writes: | On Thu, Dec 01, 2005 at 11:53:00AM -0800, Doug Ambrisko wrote: | > Kris Kennaway writes: | > | On Thu, Dec 01, 2005 at 11:32:10AM -0800, Doug Ambrisko wrote: | > | > On Thursday 24 November 2005 01:27 am, Kris Kennaway wrote: | > | > > On Wed, Nov 23, 2005 at 03:02:05PM -0800, Darren Pilgrim wrote: | > | > > > Until this gets "fixed" in FreeBSD, what should those of us who are | > | > > > effectively stuck with this hardware do to avoid the problem? Does the | > | > > > problem exist in RELENG_4? | > | > > | > | > > Yes, on the same machine I first mentioned. | > | > | > | > Is this is SMP on or off? I think it might be okay if SMP if off. | > | | > | With SMP, I don't recall if I tried it without. SMP is pretty useless | > | on 4.x (often hurts more than it helps), so this may be an acceptable | > | workaround for the OP. | > | > Could you try without SMP? I wonder if the BIOS sets things up okay | > in UP mode. I saw strangeness on our PE2850's in SMP mode that didn't | > happen in UP mode. This is with 4.X. | | Without SMP, the amr and em0 devices are both assigned to irq10. | There does not appear to be an interrupt storm coming from amr | activity (60 interrupts/sec on irq10), but I don't know if this irq | configuration would have stormed anyway, and of course the shared | interrupt is sub-optimal. That seems consistant with what I've seen. FWIW, I have a storm detector in our patched amr driver. If I see more then 500 calls to the interrupt handler per tick then I wait until they slow down. This prevents the death spiral I saw in SMP mode. It looks like we'll be looking into this more since we are seeing problems when adding more NIC's in the box. To date we've been band-aiding the problem. Thanks, Doug A.