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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 C5E8EC33C8C for ; Tue, 7 Jan 2020 12:30:14 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8ECB62072A for ; Tue, 7 Jan 2020 12:30:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="IK6oKHtU" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8ECB62072A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:47806 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ionzv-0002oB-Dj for qemu-devel@archiver.kernel.org; Tue, 07 Jan 2020 07:30:12 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:53799) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ionof-0007Sg-43 for qemu-devel@nongnu.org; Tue, 07 Jan 2020 07:18:34 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ionod-00056Q-V2 for qemu-devel@nongnu.org; Tue, 07 Jan 2020 07:18:32 -0500 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:58804 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ionod-000562-R8 for qemu-devel@nongnu.org; Tue, 07 Jan 2020 07:18:31 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1578399511; 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:openpgp:openpgp; bh=JgyFu4VXRE74ffDYkkKrGkqXkGP7ShHcOWSArhXziiE=; b=IK6oKHtURajHR/Bi5oMXtvjHgQvbPG4ir0JeM9PPKKoLfHE3XR3RHDYU+DL1C5wF1oFJlp kMP3xzQQxVmW37bo2+qyh01be27dnL8YxnNRI8ogH6YoK1oB5/67Beusz1TZnwxWBVkDEg rN4fUnr+Zr8UIgyCHr6KZfhHLpCcxpc= 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-47-Q-k02HL5OHaITs_DXKZPiw-1; Tue, 07 Jan 2020 07:18:30 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 9E298107ACC5; Tue, 7 Jan 2020 12:18:29 +0000 (UTC) Received: from thuth.remote.csb (ovpn-116-116.ams2.redhat.com [10.36.116.116]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4A4927FB53; Tue, 7 Jan 2020 12:18:20 +0000 (UTC) Subject: Re: Priority of -accel (was: [PATCH] tests/qemu-iotests: Update tests to recent desugarized -accel option) To: Paolo Bonzini , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= References: <20200106130951.29873-1-philmd@redhat.com> <12334054-4ae7-e580-9727-2d322bfa2bda@redhat.com> From: Thomas Huth Openpgp: preference=signencrypt Message-ID: <58eb34db-7d32-8b0e-d9ef-98648209486b@redhat.com> Date: Tue, 7 Jan 2020 13:18:18 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <12334054-4ae7-e580-9727-2d322bfa2bda@redhat.com> Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-MC-Unique: Q-k02HL5OHaITs_DXKZPiw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , "Daniel P. Berrange" , qemu-block@nongnu.org, Markus Armbruster , qemu-devel@nongnu.org, Wainer dos Santos Moschetta , Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 07/01/2020 11.14, Paolo Bonzini wrote: > On 07/01/20 11:03, Thomas Huth wrote: >>> >>> vm = QEMUMachine(iotests.qemu_prog) >>> -vm.add_args('-machine', 'accel=kvm:tcg') >>> +vm.add_args('-accel', 'kvm', '-accel', 'tcg') >> Looking at this, I wonder whether we really want the "-accel" option to >> prioritize the accelerators in the order of appearance? A lot of other >> CLI tools give the highest priority to the last parameter instead, e.g. >> "gcc -O3 -O1" compiles with -O1, and not with -O3. >> >> Also I think it might be quite common that there are shell scripts which >> call "qemu-system-xxx -accel xyz $*" ... and if we don't invert the >> priorities of -accel, it will be impossible to override -accel in that >> case... > > Hmm, it does match "-machine accel=kvm:tcg" and in general I think it's > more self-explanatory. However, it is indeed less friendly to scripts. > On one hand those could be changed to place "-accel xyz" after $* (or > better "$@"), on the other hand we could also add a priority option to > "-accel". What do you think? I don't think we need a separate priority parameter here. But IMHO it's really rather common practice to prioritize the last option. So while it might be more "self-explanatory" to a CLI newbie if the first occurrence got the highest priority, it might be rather confusing instead for a CLI veteran...? What do others on the list here think about this? Thomas