From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH] virtio/ringtest: fix up need_event math Date: Fri, 27 Oct 2017 16:16:37 +0300 Message-ID: <20171027161336-mutt-send-email-mst@kernel.org> References: <1508982452-27245-1-git-send-email-mst@redhat.com> <20171026103647.588ac89b.cohuck@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20171026103647.588ac89b.cohuck@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Cornelia Huck Cc: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org On Thu, Oct 26, 2017 at 10:36:47AM +0200, Cornelia Huck wrote: > On Thu, 26 Oct 2017 04:48:01 +0300 > "Michael S. Tsirkin" wrote: > > > last kicked event index must be updated unconditionally: > > even if we don't need to kick, we do not want to re-check > > the same entry for events. > > > > Signed-off-by: Michael S. Tsirkin > > --- > > tools/virtio/ringtest/ring.c | 24 +++++++++++++++--------- > > 1 file changed, 15 insertions(+), 9 deletions(-) > > Acked-by: Cornelia Huck Actually it seems to sometimes trigger stalls when host and guest are on the same physical core. To trigger: ./ring --sleep --host-affinity 0 --guest-affinity 0 This worries me since it's similar to what vhost does. Still debugging - anyone see anything suspicious? > I think virtio_ring_0_9 has the same issue? I think it does, posted a patch. -- MST