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 E76FFCA9EAF for ; Fri, 25 Oct 2019 02:09:06 +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 BB83121929 for ; Fri, 25 Oct 2019 02:09:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BB83121929 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]:54284 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iNp2H-0003KP-N0 for qemu-devel@archiver.kernel.org; Thu, 24 Oct 2019 22:09:05 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37615) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iNp1T-0001bZ-0h for qemu-devel@nongnu.org; Thu, 24 Oct 2019 22:08:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iNp1R-0001L5-NI for qemu-devel@nongnu.org; Thu, 24 Oct 2019 22:08:14 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:38608 helo=huawei.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iNp1R-0001Jz-11 for qemu-devel@nongnu.org; Thu, 24 Oct 2019 22:08:13 -0400 Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 1391B89DF00BA6D9C03E; Fri, 25 Oct 2019 10:08:08 +0800 (CST) Received: from [127.0.0.1] (10.173.223.212) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.439.0; Fri, 25 Oct 2019 10:07:57 +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> <5DB1B65C.3020104@huawei.com> <20191024143859.GJ2877@work-vm> From: Zhenyu Ye Message-ID: <5DB258FC.2050506@huawei.com> Date: Fri, 25 Oct 2019 10:07:56 +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: <20191024143859.GJ2877@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: 45.249.212.32 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 22:38, Dr. David Alan Gilbert wrote: > * Zhenyu Ye (yezhenyu2@huawei.com) wrote: >> >> >> 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. > > So it depends how obvious the path is; if it's just /objects/ > followed by whatever you used with id= when you created the iothread > then I think it's easy - we just need to update the docs. > Is there a case where it's harder to know? > > Dave > You are right, it's just /objects/ followed by the id. Maybe we just need to update the docs for qom-set. >> >>>> 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 >>> >>> >>> . >>> >> > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > > > . >