From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34609) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aLVki-0006mY-JQ for qemu-devel@nongnu.org; Tue, 19 Jan 2016 07:51:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aLVkf-0001aY-Co for qemu-devel@nongnu.org; Tue, 19 Jan 2016 07:51:16 -0500 Received: from mx1.redhat.com ([209.132.183.28]:22909) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aLVkf-0001aQ-7c for qemu-devel@nongnu.org; Tue, 19 Jan 2016 07:51:13 -0500 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (Postfix) with ESMTPS id 4A03E445A7 for ; Tue, 19 Jan 2016 12:51:12 +0000 (UTC) Date: Tue, 19 Jan 2016 13:51:09 +0100 From: Kevin Wolf Message-ID: <20160119125109.GA4579@noname.redhat.com> References: <1453110880.23289.7.camel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1453110880.23289.7.camel@redhat.com> Subject: Re: [Qemu-devel] RFC: running the user interface in a thread ... List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Gerd Hoffmann Cc: David Airlie , =?iso-8859-1?Q?Marc-Andr=E9?= Lureau , qemu-devel , stefanha@redhat.com Am 18.01.2016 um 10:54 hat Gerd Hoffmann geschrieben: > Hi folks, > > I'm starting to investigate if and how we can move the user interface > code into its own thread instead of running it in the iothread and > therefore avoid blocking the guest in case some UI actions take a little > longer. > > opengl and toolkits tend to be bad at multithreading. So my idea is to > have a single thread dedicated to all the UI + rendering stuff, possibly > let even the virglrenderer run in ui thread context. > > I think we have to make that opt-in per user interface, so we can go > forward step by step. > > The ui thread will need quite some stuff provided by the mainloop. Wait > for all kinds of events (from vnc socket, x11 connection, ...). > Probably timers too. Wait for events from other threads (guest screen > updates). > > Suggestions how to tackle that? > Can I reuse the qemu mainloop code outside of the iothread? That should be possible. The block layer runs additional main loops in dataplane threads. I think AioContext is the keyword here, so that you process only events in your own UI context. I'm copying Stefan who knows this stuff a bit better than me. > Maybe it'll be better to go straight for a glib main loop? > Is it possible to wait for file handle events and posix condition > variables at the same time? > > Other notes / hints / suggestions / ideas? Kevin