From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:42869) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UIPum-0004bD-OW for qemu-devel@nongnu.org; Wed, 20 Mar 2013 16:47:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UIPuj-0005EQ-N6 for qemu-devel@nongnu.org; Wed, 20 Mar 2013 16:47:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34339) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UIPuj-0005EM-Fs for qemu-devel@nongnu.org; Wed, 20 Mar 2013 16:47:13 -0400 Date: Wed, 20 Mar 2013 22:46:16 +0200 From: "Michael S. Tsirkin" Message-ID: <20130320204616.GC23583@redhat.com> References: <5148A2F6.1070206@linux.vnet.ibm.com> <5148A5FB.1000209@redhat.com> <20130320130754.GA9777@redhat.com> <5149D2A4.2070106@linux.vnet.ibm.com> <20130320155514.GA20701@redhat.com> <5149DF08.4090209@linux.vnet.ibm.com> <20130320190633.GB22631@redhat.com> <514A19F6.3020406@linux.vnet.ibm.com> <20130320203119.GA23583@redhat.com> <514A1E64.50404@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <514A1E64.50404@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [RFC PATCH RDMA support v4: 03/10] more verbose documentation of the RDMA transport List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael R. Hines" Cc: aliguori@us.ibm.com, qemu-devel@nongnu.org, owasserm@redhat.com, abali@us.ibm.com, mrhines@us.ibm.com, gokul@us.ibm.com, Paolo Bonzini On Wed, Mar 20, 2013 at 04:39:00PM -0400, Michael R. Hines wrote: > Unmapped virtual addresses cannot be pinned for RDMA (the hardware > will break), > but there's no way to know they are unmapped without checking > another data structure. So for RDMA, when you try to register them, this will fault them in. For regular migration we really should try using vmsplice. Anyone up to it? If we do this TCP could outperform RDMA for some workloads ... -- MST