From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) (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 942DD7D40D; Wed, 22 May 2024 07:44:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.189 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716363881; cv=none; b=UXNmhjYgEGeiU8Fw51PKRWhtEAsSiOz1CSioz+mtFjFme0AT/UvJ6MsxVt0jNMwBgpT7ki2rIrUTua0jRqy4tr8owV6Pfxq3mwIEDdYzMS5R1ZMXwn6Pc+sAC8LltX+ItgSlrJmywa2phOXWoqR6hyv3RAC5iqfzo/WUyYQQmGo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716363881; c=relaxed/simple; bh=OyAYU9wdToTlNpCqVBj184wBvTfjYqMromOTV3WB6PM=; h=From:To:CC:Subject:Date:Message-ID:Content-Type:MIME-Version; b=ppHyE2VUkMzZRUwb5bg4al3xFuwj5khgJmjlSmpTbuJWg1r/1GqWcnMIYb5sGzbuUb3oGup3BoStpjkT5tTfIxW9nXSR6GSKCNE1723TSj/EEZv/UdNO3vSpy8BLRbXkj6yw0eNxiphA2zfC/WChLul53wtHvpvKuEwUIivdHKI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.189 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.162.254]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4Vkjt558xVzPmKT; Wed, 22 May 2024 15:41:33 +0800 (CST) Received: from kwepemm600019.china.huawei.com (unknown [7.193.23.64]) by mail.maildlp.com (Postfix) with ESMTPS id 9B3A11800C9; Wed, 22 May 2024 15:44:35 +0800 (CST) Received: from dggpeml500007.china.huawei.com (7.185.36.75) by kwepemm600019.china.huawei.com (7.193.23.64) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Wed, 22 May 2024 15:44:35 +0800 Received: from dggpeml500007.china.huawei.com ([7.185.36.75]) by dggpeml500007.china.huawei.com ([7.185.36.75]) with mapi id 15.01.2507.035; Wed, 22 May 2024 15:44:34 +0800 From: mengkanglai To: "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jiri Pirko , Simon Horman , Daniel Borkmann , "Sebastian Andrzej Siewior" , Lorenzo Bianconi , "netdev@vger.kernel.org" , open list CC: "Fengtao (fengtao, Euler)" , "Yanan (Euler)" Subject: cpu performance drop between 4.18 and 5.10 kernel? Thread-Topic: cpu performance drop between 4.18 and 5.10 kernel? Thread-Index: Adqr+is3Qylu3zxvSvOZrHpOxyfQ/w== Date: Wed, 22 May 2024 07:44:34 +0000 Message-ID: <9fd382fb581e47a291ed31bfe091112c@huawei.com> Accept-Language: zh-CN, en-US Content-Language: zh-CN X-MS-Has-Attach: X-MS-TNEF-Correlator: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Dear maintainers: I updated my VM kernel from 4.18 to 5.10, and found that the CPU SI usage w= as higher under the 5.10 kernel for the same udp service. I captured the flame graph and compared the two versions of kernels.=20 Kernel 5.10 compared to 4.18 napi_complete_done function added gro_normal_l= ist call (ommit 323ebb61e32b4 ("net: use listified RX for handling GRO_NORM= AL skbs") Introduced), I removed gro_normal_list from napi_complete_done in 5.= 10 kernel, CPU SI usages was same as 4.18. I don't know much about GRO, so I'm not sure if it can be modified in this = way, and the consequences of such a modification?