From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46074) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bralz-0002G8-PE for qemu-devel@nongnu.org; Tue, 04 Oct 2016 21:13:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bralu-0006cd-Mm for qemu-devel@nongnu.org; Tue, 04 Oct 2016 21:13:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46730) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bralu-0006bq-GU for qemu-devel@nongnu.org; Tue, 04 Oct 2016 21:13:22 -0400 Date: Wed, 5 Oct 2016 04:13:19 +0300 From: "Michael S. Tsirkin" Message-ID: <20161005041245-mutt-send-email-mst@kernel.org> 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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8035787f-e9ed-f493-6575-ce5282e9afe1@redhat.com> 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: Paolo Bonzini Cc: Thomas Huth , "Daniel P. Berrange" , Laurent Vivier , Peter Maydell , Stefano Stabellini , qemu-devel@nongnu.org, Alex =?iso-8859-1?Q?Benn=E9e?= 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... > > Paolo AFAIK pxe firmware typically can't handle interrupts so it polls for packets. -- MST