From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:46392) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Qnng8-0004pz-11 for qemu-devel@nongnu.org; Mon, 01 Aug 2011 04:16:55 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Qnnfc-0008Nm-Rm for qemu-devel@nongnu.org; Mon, 01 Aug 2011 04:16:47 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48515) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Qnnfc-0008Ne-Kv for qemu-devel@nongnu.org; Mon, 01 Aug 2011 04:16:16 -0400 Message-ID: <4E3660C9.3000708@redhat.com> Date: Mon, 01 Aug 2011 11:16:09 +0300 From: Avi Kivity MIME-Version: 1.0 References: <1312141678-5141-1-git-send-email-avi@redhat.com> <4E365718.2060500@web.de> <4E365B3A.7050701@web.de> In-Reply-To: <4E365B3A.7050701@web.de> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] memory: synchronize dirty bitmap before unmapping a range List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org On 08/01/2011 10:52 AM, Jan Kiszka wrote: > On 2011-08-01 09:34, Jan Kiszka wrote: > > On 2011-07-31 21:47, Avi Kivity wrote: > >> When a range is being unmapped, ask accelerators (e.g. kvm) to synchronize the > >> dirty bitmap to avoid losing information forever. > >> > >> Fixes grub2 screen update. > > > > I does. > > > > But something is still broken. As I reported before, the performance of > > grub2 startup is an order of magnitude slower than with the existing > > code. According to ftrace, we are getting tons of additional > > EPT_MISCONFIG exits over the 0xA0000 segment. But I haven't spot the > > difference yet. The effective slot setup as communicated to kvm looks > > innocent. > > I take it back: We obviously once in a while resume the guest with the > vga segment unmapped. And that, of course, ends up doing mmio instead of > plain ram accesses. > qemu-kvm.git 6b5956c573 and its predecessor fix the issue (and I think they're even faster than upstream, but perhaps I'm not objective). -- error compiling committee.c: too many arguments to function