From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756797Ab1K3Ose (ORCPT ); Wed, 30 Nov 2011 09:48:34 -0500 Received: from mx1.redhat.com ([209.132.183.28]:3534 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752433Ab1K3Osa (ORCPT ); Wed, 30 Nov 2011 09:48:30 -0500 Date: Wed, 30 Nov 2011 16:50:04 +0200 From: "Michael S. Tsirkin" To: Ohad Ben-Cohen Cc: virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Rusty Russell Subject: Re: [RFC] virtio: use mandatory barriers for remote processor vdevs Message-ID: <20111130145004.GD21413@redhat.com> References: <1322569886-13055-1-git-send-email-ohad@wizery.com> <20111129131110.GC19157@redhat.com> <20111129151958.GA31789@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 30, 2011 at 01:55:53PM +0200, Ohad Ben-Cohen wrote: > On Tue, Nov 29, 2011 at 5:19 PM, Michael S. Tsirkin wrote: > > On Tue, Nov 29, 2011 at 03:57:19PM +0200, Ohad Ben-Cohen wrote: > >> > Is an extra branch faster or slower than reverting d57ed95? > >> > >> Sorry, unfortunately I have no way to measure this, as I don't have > >> any virtualization/x86 setup. I'm developing on ARM SoCs, where > >> virtualization hardware is coming, but not here yet. > > > > You can try using the micro-benchmark in tools/virtio/. > > Hmm, care to show me exactly what do you mean ? make headers_install make -C tools/virtio/ (you'll need an empty stub for tools/virtio/linux/module.h, I just sent a patch to add that) sudo insmod tools/virtio/vhost_test/vhost_test.ko ./tools/virtio/virtio_test > Though I somewhat suspect that any micro-benchmarking I'll do with my > random ARM SoC will not have much value to real virtualization/x86 > workloads. > > Thanks, > Ohad. Real virtualization/x86 can keep using current smp_XX barriers, right? We can have some config for your kind of setup. -- MST