From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=38167 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1PmYFx-0007lc-RP for qemu-devel@nongnu.org; Mon, 07 Feb 2011 16:04:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1PmXzR-0000sk-RV for qemu-devel@nongnu.org; Mon, 07 Feb 2011 15:47:18 -0500 Received: from mail-ew0-f45.google.com ([209.85.215.45]:47614) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1PmXzR-0000sM-Ld for qemu-devel@nongnu.org; Mon, 07 Feb 2011 15:47:17 -0500 Received: by ewy10 with SMTP id 10so2682767ewy.4 for ; Mon, 07 Feb 2011 12:47:16 -0800 (PST) Date: Mon, 7 Feb 2011 21:47:12 +0100 From: "Edgar E. Iglesias" Subject: Re: [Qemu-devel] Re: [PATCH 2/7] Enable I/O thread and VNC threads by default Message-ID: <20110207204712.GC9697@laped.lan> References: <1295902845-29807-1-git-send-email-aliguori@us.ibm.com> <1295902845-29807-3-git-send-email-aliguori@us.ibm.com> <4D3DFD20.8060004@linux.vnet.ibm.com> <20110125091741.GB30239@edde.se.axis.com> <20110125133453.GC5427@amt.cnet> <20110207101255.GA20413@amt.cnet> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110207101255.GA20413@amt.cnet> List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Marcelo Tosatti Cc: Anthony Liguori , Stefan Hajnoczi , qemu-devel@nongnu.org, Anthony Liguori , Paul Brook , Arun Bharadwaj , Paulo Bonzini On Mon, Feb 07, 2011 at 08:12:55AM -0200, Marcelo Tosatti wrote: > On Tue, Jan 25, 2011 at 11:34:53AM -0200, Marcelo Tosatti wrote: > > On Tue, Jan 25, 2011 at 10:17:41AM +0100, Edgar E. Iglesias wrote: > > > On Mon, Jan 24, 2011 at 04:28:48PM -0600, Anthony Liguori wrote: > > > > On 01/24/2011 03:00 PM, Anthony Liguori wrote: > > > > > Leave the disable options for now to help with testing but these will be removed > > > > > once we're confident in the thread implementations. > > > > > > > > > > Disabled code bit rots. These have been in tree long enough that we need to > > > > > either commit to making them work or just remove them entirely. > > > > > > > > > > > > > I/O thread disables icount apparently. > > > > > > > > I'm not really sure why. Marcelo, do you know the reason > > > > qemu_calculate_timeout returns a fixed value in the I/O thread > > > > regardless of icount? > > > > > > Hi, > > > > > > The following commit hopefully fixed that issue. > > > > > > commit 225d02cd1a34d5d87e8acefbf8e244a5d12f5f8c > > > Author: Edgar E. Iglesias > > > Date: Sun Jan 23 04:44:51 2011 +0100 > > > > > > Avoid deadlock whith iothread and icount > > > > > > When using the iothread together with icount, make sure the > > > qemu_icount counter makes forward progress when the vcpu is > > > idle to avoid deadlocks. > > > > > > Signed-off-by: Edgar E. Iglesias > > > > > > See http://lists.gnu.org/archive/html/qemu-devel/2011-01/msg01602.html > > > for more info. > > > > > > One more thing I didn't mention on the email-thread or on IRC is > > > that last time I checked, qemu with io-thread was performing > > > significantly slower than non io-thread builds. That was with > > > TCG emulation (not kvm). Somewhere between 5 - 10% slower, IIRC. > > Can you recall what was the test ? Hi, didn't see this until now.. IIRC, the test was booting a CRIS linux guest. Cheers