From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LLRHp-0000yq-N6 for qemu-devel@nongnu.org; Fri, 09 Jan 2009 19:01:09 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LLRHn-0000yU-5o for qemu-devel@nongnu.org; Fri, 09 Jan 2009 19:01:08 -0500 Received: from [199.232.76.173] (port=56740 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LLRHn-0000y7-0K for qemu-devel@nongnu.org; Fri, 09 Jan 2009 19:01:07 -0500 Received: from mail2.shareable.org ([80.68.89.115]:47733) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1LLRHm-000137-He for qemu-devel@nongnu.org; Fri, 09 Jan 2009 19:01:06 -0500 Received: from jamie by mail2.shareable.org with local (Exim 4.63) (envelope-from ) id 1LLRHi-0000sd-88 for qemu-devel@nongnu.org; Sat, 10 Jan 2009 00:01:02 +0000 Date: Sat, 10 Jan 2009 00:01:02 +0000 From: Jamie Lokier Subject: Re: [Qemu-devel] Ongoing changes to the displaying code Message-ID: <20090110000101.GB1972@shareable.org> References: <4966ADD4.5090102@codesourcery.com> <4966BB7A.3090303@codemonkey.ws> <4966BEC4.7080903@codemonkey.ws> <60cad3f0901090128m23977527kf658c15ba90dbaf8@mail.gmail.com> <49676B43.2020406@codemonkey.ws> <18791.34404.878201.724561@mariner.uk.xensource.com> <4967885A.2020908@codemonkey.ws> <20090109174252.GA2193@kos.to> <49679E7F.6050504@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <49679E7F.6050504@codemonkey.ws> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Anthony Liguori wrote: > >>Of course, with the right VNC extension to support a shared memory > >>transport, I still contend VNC can be just as efficient as SDL. > >> > > > >It still puts a big speed and flexibility limit IMHO. > > Why? There's no additional memory copying. There's a very small update > latency addition. Fwiw, I agree with Anthony. If VNC performance is a concern (it probably should be when you want to do to video, or 1:1 full-screen, or 3d, or vsync-locked display), extending localhost VNC to be as good as any "native" display method can be would be the best way forward. Obviously this would involve (at least) shared memory with both the X server and QEMU, to remove all image copying and conversion when possible. Similar mechanisms can be found on Windows and MacOS X. SDL is good at some things but it's not perfect itself. It may even be better to remove SDL from QEMU proper, and provide a separate localhost-VNC-to-SDL client. (Same for the other frontends?) Localhost-VNC does not need to support the whole VNC protocol, only that used in localhost-VNC mode. The other concern with VNC might be its complexity means you really always want to use the existing VNC client library, which may not be a desirable dependency for some applications. For this, localhost-VNC being both an extension to VNC and a subset of it would be helpful, as you wouldn't have to use a full-fledged VNC client library for local GUI apps if that isn't wanted. -- Jamie