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 50C901869DA for ; Mon, 25 Mar 2024 07:17:53 +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=1711351076; cv=none; b=AhdB23OIriv4LC/G8EZ/G6Nf+d0LKJsDZ5tAAyNOtErFmb/eJRNIl5XsLkvl+/C34vw+n7KrJpodsblIaM4PqS/zJYWALU+/iBqn2rMYra0YoiKr0k1iv1suIvfmvbxNPN5ff/uSx1PByqEylK5IqpmWhinumqQcdQOm6k0CiU0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1711351076; c=relaxed/simple; bh=JtxnzxGrTffDEA0XnqvlYJualvaU/GrEhGNY/kmUU7k=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=JRk6UE7aAfBDadk/hBktpp6ayfULATH+ikfKrlibzj7qgCqwmg3PoZWrwIQ/4lrA6YkWSAQY+VkoYGuq3AnHzSTMXYvtk9xVXLVjkTu0tLoaCA7Px1gTL8OFG6Zh/xq8CmxAWlV1F67MdmMa2SBaJxAOTSHBzovKmCKTq3e8Kg8= 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=iqxWQa4i; 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="iqxWQa4i" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1711351071; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=uiAJzlkaILI73D+td4TN5g1wQlkiDXtOcSrE97onzLo=; b=iqxWQa4ih7FSTNcCG3hmgk/zPSkYlnjGB4cL9pGH4pypySHC9Igz0RcyPt/ZJQMRQ+AcJQKn9bu9O3c5sZFD3DR9s7KDRG3QN1+FitRighrrHpj+dXdGFa0bw5qp1ARFfdlBUdnMWCV8MvEi4gLvHP7K2gHSJIFT7rLZAUEmJKs= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R161e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045170;MF=hengqi@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0W3B4ysg_1711351069; Received: from 30.221.148.153(mailfrom:hengqi@linux.alibaba.com fp:SMTPD_---0W3B4ysg_1711351069) by smtp.aliyun-inc.com; Mon, 25 Mar 2024 15:17:50 +0800 Message-ID: Date: Mon, 25 Mar 2024 15:17:47 +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. > > And I remember you told us your device doesn't have such an issue. YES. Thanks, Heng > > Thanks > >> Thanks, >> Heng >> >>> Thanks