From owner-freebsd-hackers@FreeBSD.ORG Thu Apr 5 03:23:15 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id E9935106566B for ; Thu, 5 Apr 2012 03:23:15 +0000 (UTC) (envelope-from alexander@leidinger.net) Received: from mail.ebusiness-leidinger.de (mail.ebusiness-leidinger.de [217.11.53.44]) by mx1.freebsd.org (Postfix) with ESMTP id 9F1758FC19 for ; Thu, 5 Apr 2012 03:23:15 +0000 (UTC) Received: from outgoing.leidinger.net (p4FC42835.dip.t-dialin.net [79.196.40.53]) by mail.ebusiness-leidinger.de (Postfix) with ESMTPSA id 293578446D3; Thu, 5 Apr 2012 05:22:52 +0200 (CEST) Received: from unknown (IO.Leidinger.net [192.168.1.12]) by outgoing.leidinger.net (Postfix) with ESMTPS id A3D0C23A1; Thu, 5 Apr 2012 05:22:48 +0200 (CEST) Date: Thu, 5 Apr 2012 05:22:46 +0200 From: Alexander Leidinger To: Jerry Toung Message-ID: <20120405052246.00002c53@unknown> In-Reply-To: References: <20120403193124.46ad9de9@ernst.jennejohn.org> X-Mailer: Claws Mail 3.7.10cvs42 (GTK+ 2.16.6; i586-pc-mingw32msvc) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-EBL-MailScanner-Information: Please contact the ISP for more information X-EBL-MailScanner-ID: 293578446D3.AED8F X-EBL-MailScanner: Found to be clean X-EBL-MailScanner-SpamCheck: not spam, spamhaus-ZEN, SpamAssassin (not cached, score=0.39, required 6, autolearn=disabled, ALL_TRUSTED -1.00, AWL -0.60, BR_SPAMMER_URI 2.00, T_RP_MATCHES_RCVD -0.01) X-EBL-MailScanner-From: alexander@leidinger.net X-EBL-MailScanner-Watermark: 1334200972.84234@wFBhdtfxuK6bbreajlGgMw X-EBL-Spam-Status: No X-Mailman-Approved-At: Thu, 05 Apr 2012 04:25:10 +0000 Cc: freebsd-hackers Subject: Re: CAM disk I/O starvation X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 05 Apr 2012 03:23:16 -0000 On Tue, 3 Apr 2012 14:27:43 -0700 Jerry Toung wrote: > On 4/3/12, Gary Jennejohn wrote: > > > It would be interesting to see your patch. I always run HEAD but > > maybe I could use it as a base for my own mods/tests. > > > > Here is the patch This looks fair if all your disks are working at the same time (e.g. RAID only setup), but if you have a setup where you have multiple disks and only one is doing something, you limit the amount of tags which can be used. No idea what kind of performance impact this would have. What about the case where you have more disks than tags? I also noticed that you do a strncmp for "da". What about "ada" (available in 9 and 10), I would assume it suffers from the same problem. Bye, Alexander. -- http://www.Leidinger.net Alexander @ Leidinger.net: PGP ID = B0063FE7 http://www.FreeBSD.org netchild @ FreeBSD.org : PGP ID = 72077137