From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 36D16C433E0 for ; Sun, 26 Jul 2020 07:58:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0C0E02065C for ; Sun, 26 Jul 2020 07:58:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=hostfission.com header.i=@hostfission.com header.b="PvfEXW/t" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726946AbgGZH6O (ORCPT ); Sun, 26 Jul 2020 03:58:14 -0400 Received: from mail1.hostfission.com ([139.99.139.48]:58116 "EHLO mail1.hostfission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725810AbgGZH6O (ORCPT ); Sun, 26 Jul 2020 03:58:14 -0400 X-Greylist: delayed 545 seconds by postgrey-1.27 at vger.kernel.org; Sun, 26 Jul 2020 03:58:13 EDT Received: from www1.hostfission.com (www1.hostfission.com [139.99.139.52]) by mail1.hostfission.com (Postfix) with ESMTP id 4EEC04216A; Sun, 26 Jul 2020 17:49:07 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=hostfission.com; s=mail; t=1595749747; bh=5pXpIjVViNIuGvy8ExDLKr/tvQKrwNajc64XDb5pATk=; h=Date:From:To:Cc:Subject:From; b=PvfEXW/t1CKOi6Sqb0tOKQrLBxc5KhN3lBOg4b7PFpzRDwA8/XT57VjuTaAdmPZiG 0+HVeq0oxb3SKX9qBMcaz+Wkq9tz3kbm0mwXeasiO7gj9+RoNEhKTAqBoW+BoNGyWY H/6ZE/OlMRaV1z0WrNINbV0VyUOt/zkBujYgRt9g= Received: from mail.hostfission.com (www1.hostfission.com [127.0.0.1]) by www1.hostfission.com (Postfix) with ESMTP id 3480A92426; Sun, 26 Jul 2020 17:49:07 +1000 (AEST) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Sun, 26 Jul 2020 17:49:07 +1000 From: Geoffrey McRae To: hdanton@sina.com Cc: tj@kernel.org, jiangshanlai@gmail.com, linux-kernel@vger.kernel.org Subject: Poor windows VFIO performance, GPU stalls (bisected) Message-ID: <30452714b2935b530b9c2bbf2d20854a@hostfission.com> X-Sender: geoff@hostfission.com User-Agent: Roundcube Webmail/1.3.8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi All, The commit 22540ca3d00d2990a4148a13b92209c3dc5422db causes a Windows KVM guest running under QEMU with a VFIO passthrough GPU to randomly stall when using the GPU leading to the guest assuming that the driver has hung. Reverting this commit resolves the problem. The host system is configured with the following kernel arguments which may be related: isolcpus=0-5,24-29,6-11,30-35 rcu_nocbs=0-5,24-29,6-11,30-35 The system is an AMD Threadripper 2970WX on a Gigabyte x399 AORUS Gaming 7 board. It has two GPUs each being passed through to two separate KVM guests, one is an AMD Radeon 7 in a Linux guest, the other is a GeForce 1080Ti in a Windows guest. The cores used for these two guests are isolated from the host for performance reasons. Any insight as to why this is occurring would be appreciated. If you need any more information or would like to test patches please let me know. Kind Regards, Geoffrey McRae HostFission https://hostfission.com