From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: sync guest calls made async on host - SQLite performance Date: Mon, 19 Oct 2009 14:56:47 +0900 Message-ID: <4ADBFF9F.5050607@redhat.com> References: <4ACF89CB.5020406@gmail.com> <4AD1A27A.4060307@redhat.com> <20091013223714.GB16152@lst.de> <4AD5B00D.102@redhat.com> <20091014134122.GA14235@lst.de> <4AD602C8.4090603@redhat.com> <20091014170215.GA22621@lst.de> <4AD6569F.80803@codemonkey.ws> <20091015121702.GA3780@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Anthony Liguori , Matthew Tippett , Dustin Kirkland , RW , kvm@vger.kernel.org To: Christoph Hellwig Return-path: Received: from mx1.redhat.com ([209.132.183.28]:16640 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751423AbZJSF5A (ORCPT ); Mon, 19 Oct 2009 01:57:00 -0400 In-Reply-To: <20091015121702.GA3780@lst.de> Sender: kvm-owner@vger.kernel.org List-ID: On 10/15/2009 09:17 PM, Christoph Hellwig wrote: > > So can we please get the detailed setup where this happens, that is: > > Here's a setup where it doesn't happen (pwrite() + fdatasync() get to the disk): > filesystem used in the guest > ext4 > any volume manager / software raid used in the guest > lvm over one physical device > kernel version in the guest > 2.6.30.8 (F11) > image format used > qcow2 > qemu command line including caching mode, using ide/scsi/virtio, etc > -drive file=...,if=virtio > qemu/kvm version > qemu-kvm.git master > filesystem used in the host > ext4 > any volume manager / software raid used in the host > lvm over one device > kernel version in the host > 2.6.30.8 (F11) So it seems this is no longer an issue, but may be an issue on older setups. I suspect LVM as it used to swallow barriers. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.