From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932379AbdJ0NQo (ORCPT ); Fri, 27 Oct 2017 09:16:44 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35134 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752077AbdJ0NQj (ORCPT ); Fri, 27 Oct 2017 09:16:39 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 2AE31C057FA8 Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx08.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=mst@redhat.com Date: Fri, 27 Oct 2017 16:16:37 +0300 From: "Michael S. Tsirkin" To: Cornelia Huck Cc: linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH] virtio/ringtest: fix up need_event math 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-Disposition: inline In-Reply-To: <20171026103647.588ac89b.cohuck@redhat.com> X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Fri, 27 Oct 2017 13:16:39 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.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