From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=52024 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PrQx1-0008WG-9B for qemu-devel@nongnu.org; Mon, 21 Feb 2011 03:17:00 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PrQx0-0002Qa-Dw for qemu-devel@nongnu.org; Mon, 21 Feb 2011 03:16:59 -0500 Received: from mail-ew0-f52.google.com ([209.85.215.52]:33606) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PrQx0-0002QV-6w for qemu-devel@nongnu.org; Mon, 21 Feb 2011 03:16:58 -0500 Received: by ewy10 with SMTP id 10so403955ewy.11 for ; Mon, 21 Feb 2011 00:16:57 -0800 (PST) Sender: Paolo Bonzini Message-ID: <4D621F77.3080802@redhat.com> Date: Mon, 21 Feb 2011 09:16:55 +0100 From: Paolo Bonzini MIME-Version: 1.0 References: In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: How can I understand CONFIG_IO_THREAD ? List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: wang sheng Cc: qemu-devel@nongnu.org On 02/21/2011 04:13 AM, wang sheng wrote: > What is the purpose of io_thread desigment in qemu ? There was a lengthy thread recently explaining how it helps fixing a possibly delay in handling I/O. It is also useful for KVM, where you have one I/O thread and multiple CPU threads. This way, KVM can implement "real" SMP (i.e. multiple virtual CPUs running concurrently). Paolo