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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 7AB75CA9EAF for ; Thu, 24 Oct 2019 15:58:53 +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 4E05320663 for ; Thu, 24 Oct 2019 15:58:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4E05320663 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:45862 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iNfVk-0008Oe-Cj for qemu-devel@archiver.kernel.org; Thu, 24 Oct 2019 11:58:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:40137) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iNeC2-0006Mm-Hx for qemu-devel@nongnu.org; Thu, 24 Oct 2019 10:34:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iNeBy-0002s8-1E for qemu-devel@nongnu.org; Thu, 24 Oct 2019 10:34:23 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:37590 helo=huawei.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iNeBw-0002pc-64 for qemu-devel@nongnu.org; Thu, 24 Oct 2019 10:34:21 -0400 Received: from DGGEMS413-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id BF0ABA80BB188A86E9F7; Thu, 24 Oct 2019 22:34:14 +0800 (CST) Received: from [127.0.0.1] (10.173.223.212) by DGGEMS413-HUB.china.huawei.com (10.3.19.213) with Microsoft SMTP Server id 14.3.439.0; Thu, 24 Oct 2019 22:34:05 +0800 Subject: Re: [RFC PATCH] iothread: add set_iothread_poll_* commands To: "Dr. David Alan Gilbert" References: <5DAEB9D3.3080503@huawei.com> <20191023151903.GI9574@stefanha-x1.localdomain> <5DB1ACF2.9080500@huawei.com> <20191024135645.GG2877@work-vm> From: Zhenyu Ye Message-ID: <5DB1B65C.3020104@huawei.com> Date: Thu, 24 Oct 2019 22:34:04 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 MIME-Version: 1.0 In-Reply-To: <20191024135645.GG2877@work-vm> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.173.223.212] X-CFilter-Loop: Reflected X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 45.249.212.35 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: qemu-devel@nongnu.org, xiexiangyou@huawei.com, jiangyiwen , Stefan Hajnoczi , pbonzini@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 2019/10/24 21:56, Dr. David Alan Gilbert wrote: > * Zhenyu Ye (yezhenyu2@huawei.com) wrote: >> >> >> On 2019/10/23 23:19, Stefan Hajnoczi wrote: >>> On Tue, Oct 22, 2019 at 04:12:03PM +0800, yezhenyu (A) wrote: >>>> Since qemu2.9, QEMU added three AioContext poll parameters to struct >>>> IOThread: poll_max_ns, poll_grow and poll_shrink. These properties are >>>> used to control iothread polling time. >>>> >>>> However, there isn't properly hmp commands to adjust them when the VM is >>>> alive. It's useful to adjust them online when observing the impact of >>>> different property value on performance. >>>> >>>> This patch add three hmp commands to adjust iothread poll-* properties >>>> for special iothread: >>>> >>>> set_iothread_poll_max_ns: set the maximum polling time in ns; >>>> set_iothread_poll_grow: set how many ns will be added to polling time; >>>> set_iothread_poll_shrink: set how many ns will be removed from polling >>>> time. >>>> >>>> Signed-off-by: Zhenyu Ye >>>> --- >>>> hmp-commands.hx | 42 ++++++++++++++++++++ >>>> hmp.c | 30 +++++++++++++++ >>>> hmp.h | 3 ++ >>>> include/sysemu/iothread.h | 6 +++ >>>> iothread.c | 80 +++++++++++++++++++++++++++++++++++++++ >>>> qapi/misc.json | 23 +++++++++++ >>>> 6 files changed, 184 insertions(+) >>> >>> poll-max-ns, poll-grow, poll-shrink are properties of IOThread objects. >>> They can already be modified at runtime using: >>> >>> $ qemu -object iothread,id=iothread1 >>> (qemu) qom-set /objects/iothread1 poll-max-ns 100000 >>> >>> I think there is no need for a patch. >>> >>> Stefan >>> >> >> Thanks for your review. I have considered using the `qom-set` command to modify >> IOThread object's properties, however, this command is not friendly to primary >> users. The help info for this command is only: >> >> qom-set path property value -- set QOM property >> >> It's almost impossible to get the correct `path` parameter for primary user. > > Is this just a matter of documenting how to do it? > > It sounds like there's no need for a new QMP command though; if you > want an easier HMP command I'd probably still take it (because HMP is ok > at having things for convenience) - but not if it turns out that just > adding a paragraph of documentation is enough. > > Dave > I will show the differences in QMP and HMP: If I want to set iothread1.poll-max-ns=1000 and iothread1.poll-grow=2: Without this patch: QMP command: qom-set /objects/iothread1 poll-max-ns 1000 qom-set /objects/iothread1 poll-grow 2 HMP command: { "execute": "qom-set", "arguments": { "path": "/objects/iothread1", "property": "poll-max-ns", "value": 1000 } } { "execute": "qom-set", "arguments": { "path": "/objects/iothread1", "property": "poll-grow", "value": 2} } with this patch: QMP command: iothread_set_parameter iothread1 max-ns 1000 iothread_set_parameter iothread1 grow 2 HMP command: { "execute": "set-iothread-poll-params", "arguments': { "iothread-id": "iothread1", "max-ns": 1000, "grow": 2 } } I think the inconvenience of qom-set is how to get the correct `path` parameter. Anyway, I will consider your advice. >> This patch provides a more convenient and easy-use hmp&qmp interface to modify >> these IOThread properties. I think this patch still has a little value. >> >> And I can implement this patch compactly by reusing your code. >> >> Waiting for your reply. >> > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > > > . >