From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-110.freemail.mail.aliyun.com (out30-110.freemail.mail.aliyun.com [115.124.30.110]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 37F3A14F103 for ; Mon, 25 Mar 2024 08:22:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.110 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711354946; cv=none; b=T9nTV9ps/leu6aESkNMqVdh6Udoh+VdLh0ZHum5VJ5yVdEZ2Y4q8IdAXQts99scL8KwzHc4kgubWNQwLEjzJB0wVh2hKKnlz8Twcubrjb5CrelqGb4/DAKbkOWKH2rttKnuwJaLTr2Rwv8lMROxs9/tw1H2kuby2WwzAMHAzXiw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711354946; c=relaxed/simple; bh=b9FmiI9Sq+TCqOP+A6HV/teAqMiEHMNA8KXPT7w4IrE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=D7LgTa9+1TQ1w9jbu3yNJlDE6rcrzlqet616F4N9hWkd2b+L9jemqiT1S/a4bmmd0okNUKSNgSQukoG3ufC/LiFQQ/i2TSOkpkL1ynbLNWgWFkBFsXhce5NjD3cv8xS2baeST5xSjmpqKeWKjjgeBdXHzBjZaQ9/EYUEFT4WQO8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=Cqu3ww2+; arc=none smtp.client-ip=115.124.30.110 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="Cqu3ww2+" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1711354941; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=bEzipBhG/k4adub5cfWHCJ/NQav+qWnAiGWpYm5ooOA=; b=Cqu3ww2+6svRSgPr6tBIi+07xrbC1vhd+zMbMnfZ/qPvh/SrPv5/75e0u9lUE5+2ibKihkbf5Cazvyojeq0xTZWOTgDFZb5tob1KsNJUrHskKHrHIs8C4+Kxqip+P3mdw+k7Q+DVaBl+hd+8kFBzbfkL0MLs2KdYxZNppXH4bsY= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R201e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018046060;MF=hengqi@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0W3CFn.C_1711354940; Received: from 30.221.148.153(mailfrom:hengqi@linux.alibaba.com fp:SMTPD_---0W3CFn.C_1711354940) by smtp.aliyun-inc.com; Mon, 25 Mar 2024 16:22:21 +0800 Message-ID: <36ce2bbf-3a31-4c01-99f3-1875f79e2831@linux.alibaba.com> Date: Mon, 25 Mar 2024 16:22:17 +0800 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] virtio-net: reduce the CPU consumption of dim worker To: Jason Wang Cc: netdev@vger.kernel.org, virtualization@lists.linux.dev, "Michael S. Tsirkin" , Jakub Kicinski , Paolo Abeni , Eric Dumazet , "David S. Miller" , Xuan Zhuo References: <1711021557-58116-1-git-send-email-hengqi@linux.alibaba.com> <1711021557-58116-3-git-send-email-hengqi@linux.alibaba.com> <5708312a-d8eb-40ee-88a9-e16930b94dda@linux.alibaba.com> From: Heng Qi In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit 在 2024/3/25 下午3:56, Jason Wang 写道: > On Mon, Mar 25, 2024 at 3:18 PM Heng Qi wrote: >> >> >> 在 2024/3/25 下午1:57, Jason Wang 写道: >>> On Mon, Mar 25, 2024 at 10:21 AM Heng Qi wrote: >>>> >>>> 在 2024/3/22 下午1:19, Jason Wang 写道: >>>>> On Thu, Mar 21, 2024 at 7:46 PM Heng Qi wrote: >>>>>> Currently, ctrlq processes commands in a synchronous manner, >>>>>> which increases the delay of dim commands when configuring >>>>>> multi-queue VMs, which in turn causes the CPU utilization to >>>>>> increase and interferes with the performance of dim. >>>>>> >>>>>> Therefore we asynchronously process ctlq's dim commands. >>>>>> >>>>>> Signed-off-by: Heng Qi >>>>> I may miss some previous discussions. >>>>> >>>>> But at least the changelog needs to explain why you don't use interrupt. >>>> Will add, but reply here first. >>>> >>>> When upgrading the driver's ctrlq to use interrupt, problems may occur >>>> with some existing devices. >>>> For example, when existing devices are replaced with new drivers, they >>>> may not work. >>>> Or, if the guest OS supported by the new device is replaced by an old >>>> downstream OS product, it will not be usable. >>>> >>>> Although, ctrlq has the same capabilities as IOq in the virtio spec, >>>> this does have historical baggage. >>> I don't think the upstream Linux drivers need to workaround buggy >>> devices. Or it is a good excuse to block configure interrupts. >> Of course I agree. Our DPU devices support ctrlq irq natively, as long >> as the guest os opens irq to ctrlq. >> >> If other products have no problem with this, I would prefer to use irq >> to solve this problem, which is the most essential solution. > Let's do that. Ok, will do. Do you have the link to the patch where you previously modified the control queue for interrupt notifications. I think a new patch could be made on top of it, but I can't seem to find it. Thanks, Heng > > Thanks > >>> And I remember you told us your device doesn't have such an issue. >> YES. >> >> Thanks, >> Heng >> >>> Thanks >>> >>>> Thanks, >>>> Heng >>>> >>>>> Thanks