From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1M8c3N-00057J-8I for qemu-devel@nongnu.org; Mon, 25 May 2009 11:25:30 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1M8c3H-00053P-Eo for qemu-devel@nongnu.org; Mon, 25 May 2009 11:25:28 -0400 Received: from [199.232.76.173] (port=47201 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1M8c3G-00052u-W9 for qemu-devel@nongnu.org; Mon, 25 May 2009 11:25:23 -0400 Received: from pf.freedaemonhosting.com ([66.210.104.252]:35757 helo=FreeDaemonHosting.com) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1M8c3G-0001FG-HZ for qemu-devel@nongnu.org; Mon, 25 May 2009 11:25:22 -0400 Date: Mon, 25 May 2009 10:24:47 -0500 From: "Todd T. Fries" Subject: Re: [Qemu-devel] Do we need CONFIG_AIO? Message-ID: <20090525152447.GA16679@fries.net> References: <20090525082151.GA4107@lst.de> <4A1A85B4.3060200@eu.citrix.com> <20090525133554.GA16351@fries.net> <4A1AA162.1050403@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A1AA162.1050403@redhat.com> Reply-To: todd@fries.net List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: "qemu-devel@nongnu.org" , Christoph Hellwig , Stefano Stabellini Penned by Avi Kivity on 20090525 16:47.14, we have: > Todd T. Fries wrote: >> Penned by Stefano Stabellini on 20090525 12:49.08, we have: >> | Christoph Hellwig wrote: >> | | > Currently all aio code in the raw-posix block driver depends on a >> | > CONFIG_AIO symbol that gets set based on the availability of the >> | > pthreads library. Beeing able to rely on unconditional aio support >> | > means we could remove the whole code for plain bdrv_read/bdrv_write >> | > in raw-posix.c which is about 300 lines of code and a duplicated code >> | > path. Is there any Posix-ish platform qemu supports that does not >> | > have pthreads support? >> | > | | MiniOS. >> | I would appreciate if you keep that flag. >> >> You seem to be under the illusion that pthreads implies AIO. >> > > He isn't. > >> OpenBSD has two flavors of threads libraries (arguably one is not >> fit for consumption yet) and neither provide AIO. >> >> This flag is most useful for OpenBSD as well. >> > > Qemu's CONFIG_AIO requires thread support from the host, not posix aio > support. If thats the way things work, great. I just recall when AIO made its debut in qemu we had to figure out some strange workarounds.. -- Todd Fries .. todd@fries.net _____________________________________________ | \ 1.636.410.0632 (voice) | Free Daemon Consulting, LLC \ 1.405.227.9094 (voice) | http://FreeDaemonConsulting.com \ 1.866.792.3418 (FAX) | "..in support of free software solutions." \ 250797 (FWD) | \ \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\ 37E7 D3EB 74D0 8D66 A68D B866 0326 204E 3F42 004A http://todd.fries.net/pgp.txt