From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1Cs7rg-0006D0-8Q for qemu-devel@nongnu.org; Fri, 21 Jan 2005 18:06:52 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1Cs7rf-0006CP-5I for qemu-devel@nongnu.org; Fri, 21 Jan 2005 18:06:51 -0500 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Cs7mf-0003xR-BW for qemu-devel@nongnu.org; Fri, 21 Jan 2005 18:01:41 -0500 Received: from [65.74.133.9] (helo=mail.codesourcery.com) by monty-python.gnu.org with esmtp (TLSv1:DES-CBC3-SHA:168) (Exim 4.34) id 1Cs7Bs-0006fJ-3v for qemu-devel@nongnu.org; Fri, 21 Jan 2005 17:23:40 -0500 From: Paul Brook Subject: Re: [Qemu-devel] Re: Qemu-devel Digest, Vol 22, Issue 46 Date: Fri, 21 Jan 2005 22:23:33 +0000 References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200501212223.34603.paul@codesourcery.com> 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 On Friday 21 January 2005 20:53, Julian Chesterfield wrote: > >It shouldn't make a different if the host OS > >uses it > >or not. > > Excuse my ignorance but is this because there is no > potential for parallelising tasks in qemu to take advantage of idle > CPU cycles? In theory you could put CPU and system emulation in separate threads. In practice I suspect the synchronisation overhead outweighs the (small) benefit that hyperthreading gives you. I'm not even sure it's give any significant benefit on real SMP systems. Simulating multiple cpu SMP guest system on a SMP host cpus would be interesting, but that's a whole new thing. Paul