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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 715E4C432C0 for ; Tue, 26 Nov 2019 14:06:21 +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 3DC4120656 for ; Tue, 26 Nov 2019 14:06:21 +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="I2fh/ue6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3DC4120656 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]:55334 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iZbTw-0003Gu-AZ for qemu-devel@archiver.kernel.org; Tue, 26 Nov 2019 09:06:20 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:43769) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iZbIy-0007VI-C5 for qemu-devel@nongnu.org; Tue, 26 Nov 2019 08:55:02 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iZbIs-0002FZ-P5 for qemu-devel@nongnu.org; Tue, 26 Nov 2019 08:54:57 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:36037 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iZbIo-00029x-Ok for qemu-devel@nongnu.org; Tue, 26 Nov 2019 08:54:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1574776489; 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=JLRK5gadNUI3XszyOmbjNIAMyaFlJNzBbeI8Zi6bmGs=; b=I2fh/ue6kHfsNlBn6dbpNgXg+3JNsALBkPz4nlajMMEI2zZUg4Bw1+ISarELL0fD7W/539 3IS3N16fgpVlwbYgD3mP4V1rDj3zwhOAC7nJ+pLhQxwdstXVtGAOdd08mdQEnNyFfYExSa bAykR1K7zKxZV9xU5BDsTRtarwe1d4w= 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-202-JxzjvabBOB6_C8Nev8WNyQ-1; Tue, 26 Nov 2019 08:54:46 -0500 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 BBB5E107B7D4; Tue, 26 Nov 2019 13:54:44 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-116-134.ams2.redhat.com [10.36.116.134]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 3F99660C81; Tue, 26 Nov 2019 13:54:37 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 92EC51138606; Tue, 26 Nov 2019 14:54:35 +0100 (CET) From: Markus Armbruster To: Tao Xu Subject: Re: [PATCH v17 01/14] util/cutils: Add Add qemu_strtold and qemu_strtold_finite References: <20191122074826.1373-1-tao3.xu@intel.com> <20191122074826.1373-2-tao3.xu@intel.com> <8088b091-8f7c-a637-6333-e7c40935974f@intel.com> Date: Tue, 26 Nov 2019 14:54:35 +0100 In-Reply-To: <8088b091-8f7c-a637-6333-e7c40935974f@intel.com> (Tao Xu's message of "Mon, 25 Nov 2019 09:05:34 +0800") Message-ID: <87a78ispyc.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-MC-Unique: JxzjvabBOB6_C8Nev8WNyQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.120 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: "lvivier@redhat.com" , "thuth@redhat.com" , "ehabkost@redhat.com" , "mst@redhat.com" , "sw@weilnetz.de" , "Du, Fan" , "mdroth@linux.vnet.ibm.com" , "qemu-devel@nongnu.org" , "jonathan.cameron@huawei.com" , "imammedo@redhat.com" , "Liu, Jingqi" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Tao Xu writes: > Hi Markus, > > Do you have any comments on this patch and 02/14 05/14 06/14. > Thank you! These provide a new QAPI built-in type 'time'. It's like 'uint64' with an implied nanoseconds unit, and additional convenience syntax in the opts visitor and the keyval qobject input visitor. Patterned after 'size'. The only use of 'time' so far is member @latency of NumaOptions member @hmap-lb. Uses of that: * QMP command set-numa-node The convenience syntax does not apply, as QMP uses the regular qobject input visitor, not the keyval one. * CLI option -numa We first parse the option argument with QemuOpts, then convert it to NumaOptions with the opts visitor. The new built-in type 'time' gets used in -numa hmat-lb,...,latency=3DT Questions / observations: * The keyval qobject input visitor's support for 'time' appears to be unused for now. * What's the anticipated range of values for -numa hmat-lb,...,latency=3DT? I'm asking because I wonder whether we really need convenience syntax there. * Sure you want fractions? Supporting fractions for byte counts (e.g. 1.5G) has been a mixed blessing, to put it charitably. Use of fractions that aren't representable as double is not advisable. For instance, 1.1G is 1181116006 bytes rounded from 1181116006.4000001. Why would anybody want that? Use of "nice" fractions is unproblematic, but the additional convenience is rather minor. Is being able to write 1536M as 1.5G worth the trouble? Meh. With "metric" rather than "binary" suffixes, fractions provide even less convenience: 1.5ms vs. 1500us. The implementation is limited to 53 bits of precision, which has been a source of confusion. Even that has arguably taken far more patches than it's worth. We're now talking about more patches to lift the restriction. Meh. What exactly are we trying to achieve by supporting fractions? * What about all the other time-valued things in the QAPI schema? There are many more, and some of them are also visible in CLI or HMP. By providing convenience syntax for just -numa hmat-lb,...,latency=3DT, we create inconsistency. To avoid it, we'd have to hunt down all the others. But some of them aren't in nanoseconds. Your new built-in type 'time' is only applicable to the ones in nanoseconds. Do we need more built-in types? This series is at v17. I really, really want to tell you it's ready for merging. But as you see, I can't. Maybe the convenience syntax is a good idea, maybe it's a bad idea. But it's definitely not a must-have idea. If you want to pursue the idea, I recommend to split this series in two: one part without the convenience, and a second part adding it. Hopefully, we can then merge the first part without too much fuss. The second part will have to deal with the questions above. You can also shelve the idea, i.e. do just the first part now. It's what I'd do.