From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:56547) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UFKg6-0002nt-Dk for qemu-devel@nongnu.org; Tue, 12 Mar 2013 04:35:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UFKg3-0002p7-0g for qemu-devel@nongnu.org; Tue, 12 Mar 2013 04:35:22 -0400 Received: from mail-we0-x235.google.com ([2a00:1450:400c:c03::235]:44795) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UFKg2-0002p0-RR for qemu-devel@nongnu.org; Tue, 12 Mar 2013 04:35:18 -0400 Received: by mail-we0-f181.google.com with SMTP id t44so4450356wey.40 for ; Tue, 12 Mar 2013 01:35:18 -0700 (PDT) Date: Tue, 12 Mar 2013 09:35:15 +0100 From: Stefan Hajnoczi Message-ID: <20130312083515.GA18302@stefanha-thinkpad.redhat.com> References: <513DDFA3.1020308@dlhnet.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <513DDFA3.1020308@dlhnet.de> Subject: Re: [Qemu-devel] [RFC] find_next_bit optimizations List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Lieven Cc: Orit Wasserman , "qemu-devel@nongnu.org" , Corentin Chary , Paolo Bonzini On Mon, Mar 11, 2013 at 02:44:03PM +0100, Peter Lieven wrote: > I ever since had a few VMs which are very hard to migrate because of a lot of memory I/O. I found that finding the next dirty bit > seemed to be one of the culprits (apart from removing locking which Paolo is working on). > > I have to following proposal which seems to help a lot in my case. Just wanted to have some feedback. Hi Peter, Do you have any performance numbers for this patch? I'm just curious how big the win is. Stefan