From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52195) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ajHRi-00082V-H4 for qemu-devel@nongnu.org; Thu, 24 Mar 2016 22:25:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ajHRd-00024Y-IH for qemu-devel@nongnu.org; Thu, 24 Mar 2016 22:25:54 -0400 Received: from mx1.redhat.com ([209.132.183.28]:60561) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ajHRd-00024U-CR for qemu-devel@nongnu.org; Thu, 24 Mar 2016 22:25:49 -0400 Date: Fri, 25 Mar 2016 10:25:47 +0800 From: Fam Zheng Message-ID: <20160325022547.GE29171@ad.usersys.redhat.com> References: <56F4017D.7040502@windriver.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56F4017D.7040502@windriver.com> Subject: Re: [Qemu-devel] block IO thread creation question List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Chris Friesen Cc: qemu-devel@nongnu.org On Thu, 03/24 09:02, Chris Friesen wrote: > Hi, > > Could someone point me at the code for creating threads to handle > block IO? I'm seeing up to 30 threads per virtual disk, which seems > high. It is thread-pool.c, assuming you are using "aio=threads" for drive, which is the default. With the alternative, "aio=native", spawning worker threads will be much more uncommon. Fam > > In case it's related, the block devices are iSCSI with the host > acting as the initiator and exposing block devices to qemu. > > I'm particularly interested in qemu 2.2, just in case things have > changed significantly since then. > > Thanks, > Chris >