From owner-svn-src-stable@FreeBSD.ORG Thu Sep 4 11:20:15 2014 Return-Path: Delivered-To: svn-src-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 82443F34 for ; Thu, 4 Sep 2014 11:20:15 +0000 (UTC) Received: from out1-smtp.messagingengine.com (out1-smtp.messagingengine.com [66.111.4.25]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4440418E6 for ; Thu, 4 Sep 2014 11:20:15 +0000 (UTC) Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by gateway2.nyi.internal (Postfix) with ESMTP id D1EA720BF6 for ; Thu, 4 Sep 2014 07:20:12 -0400 (EDT) Received: from web6 ([10.202.2.216]) by compute3.internal (MEProxy); Thu, 04 Sep 2014 07:20:12 -0400 DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d=fastmail.net; h= message-id:from:to:cc:mime-version:content-transfer-encoding :content-type:subject:date:in-reply-to:references; s=mesmtp; bh= //Bga8PE9VdsDfjYfFHl+fLWBS4=; b=lUxOQYtCx+dS1vMOjvXtxla8Iz16TP5U HrfOC4mXthYE3NxrmhZ18F4w1p0JqzwWsXyX5l43WGSaU5g99Xa73dW+JBost6/m DIBjgsqupP9nEUkmDWP3Fg8qKCR2u/ka0nz804rV0NTifOblW2uatBwyKrjhZb2R 6ojLCjyn278= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d= messagingengine.com; h=message-id:from:to:cc:mime-version :content-transfer-encoding:content-type:subject:date:in-reply-to :references; s=smtpout; bh=//Bga8PE9VdsDfjYfFHl+fLWBS4=; b=OaujB cObefwLdyvemW5vBkkBWGDv/hnyAMaAzMPs17fa2RLByoPYkxvn8sctHN7kY0VM8 pVkhzEr9JJOpJ4ZhQVxnt9WfiYpUNyQOHkAx3ZcMGc6Q0/BV5Mx679sKGrpynDpB 8qIw55HWpPdmWwYgLosK+gGpHkqF1NblpZzu+k= Received: by web6.nyi.internal (Postfix, from userid 99) id D101E941CE3; Thu, 4 Sep 2014 07:20:11 -0400 (EDT) Message-Id: <1409829611.1620282.163554161.0056EA09@webmail.messagingengine.com> X-Sasl-Enc: 1QUA5Df2qSQonsUHQl7yKDFGDhXvrwxb8c1v/IDYDPcg 1409829611 From: Bruce Simpson To: =?ISO-8859-1?Q?Jean-S=E9bastien=20P=E9dron?= , Alexey Dokuchaev , Ed Maste MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="ISO-8859-1" X-Mailer: MessagingEngine.com Webmail Interface - ajax-a219acad Subject: Re: svn commit: r271023 - stable/10/sys/dev/vt Date: Thu, 04 Sep 2014 12:20:11 +0100 In-Reply-To: <54082B57.6070007@FreeBSD.org> References: <201409031400.s83E0bK6049810@svn.freebsd.org> <20140903140757.GA7494@FreeBSD.org> <20140903145753.GA25935@FreeBSD.org> <54082B57.6070007@FreeBSD.org> Cc: svn-src-stable@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, svn-src-stable-10@freebsd.org X-BeenThere: svn-src-stable@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: SVN commit messages for all the -stable branches of the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 04 Sep 2014 11:20:15 -0000 On Thu, 4 Sep 2014, at 10:05, Jean-S=E9bastien P=E9dron wrote: > Unfortunately, reading from the video memory is very expensive. The new > version of vt_vga never reads from the video memory. Instead, it uses > the console history to know what those 8 pixels should look like and > write one byte which doesn't need further processing. ...=20 > Those two problems combined explain the slownness of vt(4), especially > with discrete GPU and virtual machines; i915 users were mostly spared. It may be a good idea to monitor the performance of vt(4) under virtual KVM systems (e.g. Supermicro IPMI, VMware VNC, Cisco UCS etc.) for the following reasons: 1) users of FreeBSD are likely to rely on them for operations, 2) many of these systems already work along similar principles (i.e. delta compression), 3) to be sure that cascaded updates don't cause additional display latency. --=20 BMS (sent via webmail)