From mboxrd@z Thu Jan 1 00:00:00 1970 From: mst@redhat.com (Michael S. Tsirkin) Date: Wed, 30 Nov 2011 16:50:04 +0200 Subject: [RFC] virtio: use mandatory barriers for remote processor vdevs In-Reply-To: References: <1322569886-13055-1-git-send-email-ohad@wizery.com> <20111129131110.GC19157@redhat.com> <20111129151958.GA31789@redhat.com> Message-ID: <20111130145004.GD21413@redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.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