From owner-svn-src-all@FreeBSD.ORG Mon Nov 24 22:19:17 2014 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 4DB18AC1; Mon, 24 Nov 2014 22:19:17 +0000 (UTC) Received: from mail-wi0-x235.google.com (mail-wi0-x235.google.com [IPv6:2a00:1450:400c:c05::235]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id E1694BA9; Mon, 24 Nov 2014 22:19:16 +0000 (UTC) Received: by mail-wi0-f181.google.com with SMTP id r20so7428310wiv.14 for ; Mon, 24 Nov 2014 14:19:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:date:from:to:cc:subject:message-id:mail-followup-to :references:mime-version:content-type:content-disposition :in-reply-to:user-agent; bh=1TEyA0cBWY2wR/ezzFAepa9HYjC3QlLc2k6KQ0qHi94=; b=OzQBGJE9J+feMGm+uahyw0uptS0EZcJHrYjKBkU1Mo9T4Ki2Qgl+fkFPO6TjMrwEdT F6GsyAeqHZZh77ZSaHU/oDWEqlrvpAbkW7+4Evv6iy3JmktH/odB3CA0NqgIYL8ynZQX YY9rMujBNdyqMLDmCYzGOm74chQT3BmwU3R1yUBczthD3nT+nO4yh/ygHW7UO3yHRZrE YRBG5MNyM325W5hk60NYdiws48LhRYRLAFKgxzFcKv4Qd3Ht2bps0O6YVTvEd+GtTX4s Anup2EJeYZw2x3RmW5vELQyD/O7OXp/TqG4EMKDzr8+WQXDlC2wCLRWfDW26Ep3l8Rxr 6Zlg== X-Received: by 10.180.77.170 with SMTP id t10mr26157237wiw.57.1416867555374; Mon, 24 Nov 2014 14:19:15 -0800 (PST) Received: from brick.home (adha29.neoplus.adsl.tpnet.pl. [79.184.156.29]) by mx.google.com with ESMTPSA id j1sm11104729wjw.25.2014.11.24.14.19.14 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 24 Nov 2014 14:19:14 -0800 (PST) Sender: =?UTF-8?Q?Edward_Tomasz_Napiera=C5=82a?= Date: Mon, 24 Nov 2014 23:19:12 +0100 From: Edward Tomasz =?utf-8?Q?Napiera=C5=82a?= To: Alexander Motin Subject: Re: svn commit: r274962 - head/sys/cam/ctl Message-ID: <20141124221912.GA8108@brick.home> Mail-Followup-To: Alexander Motin , src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org References: <201411241137.sAOBbSeF097180@svn.freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201411241137.sAOBbSeF097180@svn.freebsd.org> User-Agent: Mutt/1.5.23 (2014-03-12) Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 24 Nov 2014 22:19:17 -0000 On 1124T1137, Alexander Motin wrote: > Author: mav > Date: Mon Nov 24 11:37:27 2014 > New Revision: 274962 > URL: https://svnweb.freebsd.org/changeset/base/274962 > > Log: > Replace home-grown CTL IO allocator with UMA. > > Old allocator created significant lock congestion protecting its lists > of preallocated I/Os, while UMA provides much better SMP scalability. > The downside of UMA is lack of reliable preallocation, that could guarantee > successful allocation in non-sleepable environments. But careful code > review shown, that only CAM target frontend really has that requirement. > Fix that making that frontend preallocate and statically bind CTL I/O for > every ATIO/INOT it preallocates any way. That allows to avoid allocations > in hot I/O path. Other frontends either may sleep in allocation context > or can properly handle allocation errors. > > On 40-core server with 6 ZVOL-backed LUNs and 7 iSCSI client connections > this change increases peak performance from ~700K to >1M IOPS! Yay! :) Hell yeah!