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 BCC8DC00523 for ; Fri, 3 Jan 2020 09:13:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8E804222C4 for ; Fri, 3 Jan 2020 09:13:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="V/unXs7K" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727450AbgACJND (ORCPT ); Fri, 3 Jan 2020 04:13:03 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:46759 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725972AbgACJND (ORCPT ); Fri, 3 Jan 2020 04:13:03 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1578042782; 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=Q4QuRAE7abPlfbDQQ4rJ1Q0z69yHUykaSdUazgcIaSo=; b=V/unXs7KeEVqOeU0686PYkNlJZZupBvQunasn2tdLOeemlKWOzyf3C1IK/M79FfOLwCc4p biKNPuGK5PsNLFcTynPGz3pPNYPaFOWAp/Yc4k+CMuXD2pO9mmJTgUpzJQsj87FGJ2O42w YrKMQxUUgkIZisBsVBomC0ZbmVGbGzE= 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-23-4W9tKpGVNJuLj3UOv0tyZA-1; Fri, 03 Jan 2020 04:13:01 -0500 X-MC-Unique: 4W9tKpGVNJuLj3UOv0tyZA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 1E81D1800D42; Fri, 3 Jan 2020 09:12:59 +0000 (UTC) Received: from [10.72.12.42] (ovpn-12-42.pek2.redhat.com [10.72.12.42]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6CE505C545; Fri, 3 Jan 2020 09:12:47 +0000 (UTC) Subject: Re: [virtio-dev] Re: [PATCH v1 2/2] virtio-mmio: add features for virtio-mmio specification version 3 To: "Liu, Jiang" Cc: "Liu, Jing2" , Zha Bin , linux-kernel@vger.kernel.org, mst@redhat.com, slp@redhat.com, virtio-dev@lists.oasis-open.org, jing2.liu@intel.com, chao.p.peng@intel.com References: <85eeab19-1f53-6c45-95a2-44c1cfd39184@redhat.com> <28da67db-73ab-f772-fb00-5a471b746fc5@linux.intel.com> <683cac51-853d-c8c8-24c6-b01886978ca4@redhat.com> <42346d41-b758-967a-30b7-95aa0d383beb@linux.intel.com> <0c3d33de-3940-7895-2fe2-81de8714139c@redhat.com> <46806720-1D1C-40C3-BEE2-EDB0D4DA39BF@linux.alibaba.com> From: Jason Wang Message-ID: <7e151886-408e-2c1d-3958-77c26b8a4ac0@redhat.com> Date: Fri, 3 Jan 2020 17:12:38 +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: <46806720-1D1C-40C3-BEE2-EDB0D4DA39BF@linux.alibaba.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 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 2020/1/3 =E4=B8=8B=E5=8D=882:14, Liu, Jiang wrote: >> Ok, I get you now. >> >> But still, having fixed number of MSIs is less flexible. E.g: >> >> - for x86, processor can only deal with about 250 interrupt vectors. >> - driver may choose to share MSI vectors [1] (which is not merged but = we will for sure need it) > Thanks for the info:) > X86 systems roughly have NCPU * 200 vectors available for device interr= upts. > The proposed patch tries to map multiple event sources to an interrupt = vector, to avoid running out of x86 CPU vectors. > Many virtio mmio devices may have several or tens of event sources, and= it=E2=80=99s rare to have hundreds of event sources. > So could we treat the dynamic mapping between event sources and interru= pt vectors as an advanced optional feature? > Maybe, but I still prefer to implement it if it is not too complex.=20 Let's see Michael's opinion on this. Thanks