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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 9D40FC2D0DA for ; Wed, 25 Dec 2019 10:31:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 623A120722 for ; Wed, 25 Dec 2019 10:31:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="ioGSWS/G" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726395AbfLYKVJ (ORCPT ); Wed, 25 Dec 2019 05:21:09 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:23871 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726106AbfLYKVJ (ORCPT ); Wed, 25 Dec 2019 05:21:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1577269267; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jZKxE5DxO7ifxt1XeLzUb+gx1kehGU9I/C/p8L+AhTw=; b=ioGSWS/Gwq2oHcRqn8Am8VUb15FOg831kGmT/hZOZt71+DqDcQS9zui7LWdxrSg4SXRrKe u9LxBdK1oZS061DMlNdL4XNRxRxtpEXvKsyxnaPLKCCS2ZuEdG8thQUZXYsVdVN21ZFASD ZQEtZLD6lXof35QRVR7q4oCHF6NZrC0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-345-z3__PXNnPp6giLDjGL74hA-1; Wed, 25 Dec 2019 05:21:06 -0500 X-MC-Unique: z3__PXNnPp6giLDjGL74hA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C25E6DB21; Wed, 25 Dec 2019 10:21:04 +0000 (UTC) Received: from [10.72.12.185] (ovpn-12-185.pek2.redhat.com [10.72.12.185]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9A42060BF3; Wed, 25 Dec 2019 10:20:56 +0000 (UTC) Subject: Re: [PATCH v1 2/2] virtio-mmio: add features for virtio-mmio specification version 3 To: Zha Bin , linux-kernel@vger.kernel.org Cc: mst@redhat.com, slp@redhat.com, virtio-dev@lists.oasis-open.org, gerry@linux.alibaba.com, jing2.liu@intel.com, chao.p.peng@intel.com References: From: Jason Wang Message-ID: <229e689d-10f1-2bfb-c393-14dfa9c78971@redhat.com> Date: Wed, 25 Dec 2019 18:20:54 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/12/25 =E4=B8=8A=E5=8D=8810:50, Zha Bin wrote: > From: Liu Jiang > > Userspace VMMs (e.g. Qemu microvm, Firecracker) take advantage of using > virtio over mmio devices as a lightweight machine model for modern > cloud. The standard virtio over MMIO transport layer only supports one > legacy interrupt, which is much heavier than virtio over PCI transport > layer using MSI. Legacy interrupt has long work path and causes specifi= c > VMExits in following cases, which would considerably slow down the > performance: > > 1) read interrupt status register > 2) update interrupt status register > 3) write IOAPIC EOI register > > We proposed to update virtio over MMIO to version 3[1] to add the > following new features and enhance the performance. > > 1) Support Message Signaled Interrupt(MSI), which increases the > interrupt performance for virtio multi-queue devices > 2) Support per-queue doorbell, so the guest kernel may directly write > to the doorbells provided by virtio devices. > > The following is the network tcp_rr performance testing report, tested > with virtio-pci device, vanilla virtio-mmio device and patched > virtio-mmio device (run test 3 times for each case): > > netperf -t TCP_RR -H 192.168.1.36 -l 30 -- -r 32,1024 > > Virtio-PCI Virtio-MMIO Virtio-MMIO(MSI) > trans/s 9536 6939 9500 > trans/s 9734 7029 9749 > trans/s 9894 7095 9318 > > [1] https://lkml.org/lkml/2019/12/20/113 Thanks for the patch. Two questions after a quick glance: 1) In PCI we choose to support MSI-X instead of MSI for having extra=20 flexibility like alias, independent data and address (e.g for affinity)=20 . Any reason for not start from MSI-X? E.g having MSI-X table and PBA=20 (both of which looks pretty independent). 2) It's better to split notify_multiplexer out of MSI support to ease=20 the reviewers (apply to spec patch as well) Thanks From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: virtio-dev-return-6569-cohuck=redhat.com@lists.oasis-open.org Sender: List-Post: List-Help: List-Unsubscribe: List-Subscribe: Received: from lists.oasis-open.org (oasis-open.org [10.110.1.242]) by lists.oasis-open.org (Postfix) with ESMTP id 9118B985D7E for ; Wed, 25 Dec 2019 10:21:08 +0000 (UTC) References: From: Jason Wang Message-ID: <229e689d-10f1-2bfb-c393-14dfa9c78971@redhat.com> Date: Wed, 25 Dec 2019 18:20:54 +0800 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US Subject: [virtio-dev] Re: [PATCH v1 2/2] virtio-mmio: add features for virtio-mmio specification version 3 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable To: Zha Bin , linux-kernel@vger.kernel.org Cc: mst@redhat.com, slp@redhat.com, virtio-dev@lists.oasis-open.org, gerry@linux.alibaba.com, jing2.liu@intel.com, chao.p.peng@intel.com List-ID: On 2019/12/25 =E4=B8=8A=E5=8D=8810:50, Zha Bin wrote: > From: Liu Jiang > > Userspace VMMs (e.g. Qemu microvm, Firecracker) take advantage of using > virtio over mmio devices as a lightweight machine model for modern > cloud. The standard virtio over MMIO transport layer only supports one > legacy interrupt, which is much heavier than virtio over PCI transport > layer using MSI. Legacy interrupt has long work path and causes specific > VMExits in following cases, which would considerably slow down the > performance: > > 1) read interrupt status register > 2) update interrupt status register > 3) write IOAPIC EOI register > > We proposed to update virtio over MMIO to version 3[1] to add the > following new features and enhance the performance. > > 1) Support Message Signaled Interrupt(MSI), which increases the > interrupt performance for virtio multi-queue devices > 2) Support per-queue doorbell, so the guest kernel may directly write > to the doorbells provided by virtio devices. > > The following is the network tcp_rr performance testing report, tested > with virtio-pci device, vanilla virtio-mmio device and patched > virtio-mmio device (run test 3 times for each case): > > =09netperf -t TCP_RR -H 192.168.1.36 -l 30 -- -r 32,1024 > > =09=09Virtio-PCI Virtio-MMIO Virtio-MMIO(MSI) > =09trans/s=09 9536=096939=09=099500 > =09trans/s=09 9734=097029=09=099749 > =09trans/s=09 9894=097095=09=099318 > > [1] https://lkml.org/lkml/2019/12/20/113 Thanks for the patch. Two questions after a quick glance: 1) In PCI we choose to support MSI-X instead of MSI for having extra=20 flexibility like alias, independent data and address (e.g for affinity)=20 . Any reason for not start from MSI-X? E.g having MSI-X table and PBA=20 (both of which looks pretty independent). 2) It's better to split notify_multiplexer out of MSI support to ease=20 the reviewers (apply to spec patch as well) Thanks --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscribe@lists.oasis-open.org For additional commands, e-mail: virtio-dev-help@lists.oasis-open.org