From owner-freebsd-scsi@FreeBSD.ORG Fri Apr 30 05:16:37 2010 Return-Path: Delivered-To: freebsd-scsi@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id F24371065670; Fri, 30 Apr 2010 05:16:37 +0000 (UTC) (envelope-from mavbsd@gmail.com) Received: from fg-out-1718.google.com (fg-out-1718.google.com [72.14.220.153]) by mx1.freebsd.org (Postfix) with ESMTP id 277C58FC13; Fri, 30 Apr 2010 05:16:36 +0000 (UTC) Received: by fg-out-1718.google.com with SMTP id 22so3507762fge.13 for ; Thu, 29 Apr 2010 22:16:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:sender:message-id:date:from :user-agent:mime-version:to:cc:subject:references:in-reply-to :x-enigmail-version:content-type:content-transfer-encoding; bh=aQ82ou089T2F+nd68fIj1Hq0FJnAK1p2WNs8zlVicRo=; b=FRjwiI6ybkmOtXYZAcGqEG+7R7mS7mXnHlGx10o1pIccolCU9+GEZ23PUcHhky0OyA MrFMj0r9S8JAgG2TyZxPjpouYzbO5wEF8WBEGRvAxJ0oZaMpqqVxjQHmmOjCyxQTdnko 4A4JQH6ke9DC/oIennO2t7im4hU4RffDKk7jY= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:x-enigmail-version:content-type :content-transfer-encoding; b=J307jOdjm9Jnm9HT7XVFTGiXucxvVT6tvNlUl5bfFeV0nHaUGLxk1LqfdXJnU2PXen sVeZ5Ksi6bPj/D72R3EUKDEnj9NJ0VBzZ5+ORrps6ycbJPh0LM+Cd8faymeJ744xH8GN uUduXA/OLwRdfifadsmBVvHM699wV1Zw7psYk= Received: by 10.102.7.12 with SMTP id 12mr5868608mug.104.1272604587752; Thu, 29 Apr 2010 22:16:27 -0700 (PDT) Received: from mavbook.mavhome.dp.ua (pc.mavhome.dp.ua [212.86.226.226]) by mx.google.com with ESMTPS id u26sm7245722mug.55.2010.04.29.22.16.26 (version=SSLv3 cipher=RC4-MD5); Thu, 29 Apr 2010 22:16:27 -0700 (PDT) Sender: Alexander Motin Message-ID: <4BDA679B.1000706@FreeBSD.org> Date: Fri, 30 Apr 2010 08:16:11 +0300 From: Alexander Motin User-Agent: Thunderbird 2.0.0.24 (X11/20100402) MIME-Version: 1.0 To: Scott Long References: <4BD98DE2.8020703@FreeBSD.org> <4A883035-3570-4FCC-B8EB-F205BD6D640D@samsco.org> <4BDA6310.10902@FreeBSD.org> <221F6444-3102-4CD7-A1A7-1DF4352E7F50@samsco.org> In-Reply-To: <221F6444-3102-4CD7-A1A7-1DF4352E7F50@samsco.org> X-Enigmail-Version: 0.96.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: freebsd-scsi@FreeBSD.org, FreeBSD Stable , Pete French , Robert Noland Subject: Re: MFC of "Large set of CAM improvements" breaks I/O to Adaptec 29160 SCSI controller X-BeenThere: freebsd-scsi@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: SCSI subsystem List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 30 Apr 2010 05:16:38 -0000 Scott Long wrote: > On Apr 29, 2010, at 10:56 PM, Alexander Motin wrote: >> Scott Long wrote: >>> On Apr 29, 2010, at 7:47 AM, Robert Noland wrote: >>>> Scott Long wrote: >>>>> On Apr 29, 2010, at 2:50 AM, Pete French wrote: >>>>>>> Thanks. First step successful - I can steadily reproduce problem on >>>>>>> CURRENT. raidtest with 200 I/O streams over gmirror of two disks on same >>>>>>> channel triggers issue in seconds. Any I/O on channel dying after both >>>>>>> disks report "Queue full" error same time. The rest of system works >>>>>>> fine. If I preliminarily manually adjust queue depth of one disk - >>>>>>> everything works fine. I'll investigate it tomorrow. >>>>>> Glad you have managed to dupliate it - the queue depth thing is >>>>>> inetersting, what changes did you make ? I can try them here and see >>>>>> if they improve the situation on either of my two machines. >>>>>> >>>>> For the record, queue-full is a common, expected condition in CAM. It's not something that should be avoided =-) >>>> Should we maybe have a counter in sysctl rather than flooding the console with these messages then? >>> That's a pretty good idea. I'll make it happen. >> It is already hidden behind bootverbose. Hiding it deeper will make >> unclear why CAM requeues the rest of commands (also reported under >> bootverbose). I've tuned log messages a bit recently and they seem to be >> more consistent and readable now IMHO. > > We used to run FreeBSD at Yahoo with bootverbose turned on in order to help with debugging. After years of doing this, I finally turned bootverbose off last year, partially because of the excessive console spam produced by these queue-full messages. Even when we were writing the ahc/ahd drivers at Adaptec years ago, I never really liked these messages, and we rarely ran with bootverbose turned on unless we were actively developing code or debugging a problem. I like Robert's suggestion because not only does it make running with bootverbose less painful, it can also provide counters and also calculate and report rate measurements that might be more useful than just the printf. > > If you feel strongly against it, I won't push it, but I do like the suggestion. No. I just wanted to say that requeue messages massively logged in that case are even less informative for regular user. -- Alexander Motin