From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46507) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1brgWk-0000Mk-NH for qemu-devel@nongnu.org; Wed, 05 Oct 2016 03:22:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1brgWf-000623-Lx for qemu-devel@nongnu.org; Wed, 05 Oct 2016 03:22:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:32934) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1brgWf-00061z-FN for qemu-devel@nongnu.org; Wed, 05 Oct 2016 03:22:01 -0400 References: <1475580648-6470-1-git-send-email-lvivier@redhat.com> <1475580648-6470-2-git-send-email-lvivier@redhat.com> <4a11fc7e-ccec-2252-c356-a0ca3466bbf0@redhat.com> <912a8fc8-47bd-fffe-60ff-0cd7b006402c@redhat.com> <20161004133114.GL5578@redhat.com> <44d24209-9901-be03-83fa-707ac12b29b4@redhat.com> <8035787f-e9ed-f493-6575-ce5282e9afe1@redhat.com> <20161005041245-mutt-send-email-mst@kernel.org> From: Paolo Bonzini Message-ID: <8d312bec-48e4-e4f5-6e8c-623ce7dbec07@redhat.com> Date: Wed, 5 Oct 2016 09:21:55 +0200 MIME-Version: 1.0 In-Reply-To: <20161005041245-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 1/2] accel: allows to select the "best" accelerator List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: Thomas Huth , "Daniel P. Berrange" , Laurent Vivier , Peter Maydell , Stefano Stabellini , qemu-devel@nongnu.org, =?UTF-8?Q?Alex_Benn=c3=a9e?= On 05/10/2016 03:13, Michael S. Tsirkin wrote: > On Tue, Oct 04, 2016 at 07:16:49PM +0200, Paolo Bonzini wrote: >> >> >> On 04/10/2016 16:18, Thomas Huth wrote: >>>>>>> Using only tcg has also some disadvantages: For some tests, it's >>>>>>> interesting to know whether they also work properly with KVM (e.g. >>>>>>> migration tests), and only using tcg by default slows down the "make >>>>>>> check" quite a bit - which might become an issue now that we're adding >>>>>>> more and more tests. >>>>> >>>>> Which tests are you seeing a slow-down for ? >>> Well, everything that is using accel=tcg in tests/ could be accelerated. >>> For example, the new ipv6/ppc64 unit test is quite slow with TCG: >>> >>> sudo QTEST_QEMU_BINARY=ppc64-softmmu/qemu-system-ppc64 time tests/pxe-test >>> >>> 48.46user 0.07system 0:48.48elapsed >> >> Could that point to a firmware bug? 10 network-bound seconds for a boot >> makes some sense, but 10 CPU-bound seconds don't... > > AFAIK pxe firmware typically can't handle interrupts > so it polls for packets. Still wouldn't be appreciably slower when emulating. Paolo