From patchwork Mon Oct 24 21:38:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nick Child X-Patchwork-Id: 13018256 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B79D9C38A2D for ; Mon, 24 Oct 2022 23:19:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230358AbiJXXSz (ORCPT ); Mon, 24 Oct 2022 19:18:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46026 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230336AbiJXXSa (ORCPT ); Mon, 24 Oct 2022 19:18:30 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2A5972E25E9 for ; Mon, 24 Oct 2022 14:38:59 -0700 (PDT) Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 29OLGJso003162 for ; Mon, 24 Oct 2022 21:38:44 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : content-transfer-encoding : mime-version; s=pp1; bh=zDi5MyIfhVNkrw7FtYNDU4o3zaqIRO+PWC9NNdAJuKk=; b=lEIBfqiK3L2A9Zn8b7iRlfa/oB5LOfYPvmzO7XI0X+xAjOkt1mbKdDYErH96uDTBWR3U yUrf2UMv063laIpZd4c1KFzm4M8gqfopvEd+FSRtzGif9gS9n4VKG7rX2qTOL+3+OXGh CD3zPLl6ee8uja/0knwjlT8Ye3YIBlU5p3r0plsVjFOlRvl74v3h0lUwgzByL1EuFOu2 yk2YJWOZFk824LQkMdjERzJ3GfKQvxpvd5DCLzwHIf4pQnVp9AipM3fqFmpV0ppRtOpz P1X36TvHqFLpl0BcgT3LCiWRtfN/F8Hz1AXB/uulb8sU2tZKPSUAXkXylGMSSZ1NRTv2 DA== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3ke200sm8r-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT) for ; Mon, 24 Oct 2022 21:38:43 +0000 Received: from m0098399.ppops.net (m0098399.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 29OLGLcv003318 for ; Mon, 24 Oct 2022 21:38:43 GMT Received: from ppma02wdc.us.ibm.com (aa.5b.37a9.ip4.static.sl-reverse.com [169.55.91.170]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3ke200sm7r-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 24 Oct 2022 21:38:43 +0000 Received: from pps.filterd (ppma02wdc.us.ibm.com [127.0.0.1]) by ppma02wdc.us.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 29OLZQx5021156; Mon, 24 Oct 2022 21:38:42 GMT Received: from b03cxnp07029.gho.boulder.ibm.com (b03cxnp07029.gho.boulder.ibm.com [9.17.130.16]) by ppma02wdc.us.ibm.com with ESMTP id 3kdytvscva-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 24 Oct 2022 21:38:42 +0000 Received: from smtpav02.dal12v.mail.ibm.com ([9.208.128.128]) by b03cxnp07029.gho.boulder.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 29OLccWg41419088 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 24 Oct 2022 21:38:38 GMT Received: from smtpav02.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id DF92C58065; Mon, 24 Oct 2022 21:38:38 +0000 (GMT) Received: from smtpav02.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 547C25805A; Mon, 24 Oct 2022 21:38:38 +0000 (GMT) Received: from li-8d37cfcc-31b9-11b2-a85c-83226d7135c9.ibm.com (unknown [9.65.197.49]) by smtpav02.dal12v.mail.ibm.com (Postfix) with ESMTP; Mon, 24 Oct 2022 21:38:38 +0000 (GMT) From: Nick Child To: netdev@vger.kernel.org Cc: nick.child@ibm.com, dave.taht@gmail.com, Nick Child Subject: [RFC PATCH net-next 0/1] ibmveth: Implement BQL Date: Mon, 24 Oct 2022 16:38:27 -0500 Message-Id: <20221024213828.320219-1-nnac123@linux.ibm.com> X-Mailer: git-send-email 2.31.1 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: xatmI735MCarRiYPoF-Vm48GbsehPYJa X-Proofpoint-GUID: ujgkPNYw7VZ3C7x41fTOwc30OLUM8Dyt X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.895,Hydra:6.0.545,FMLib:17.11.122.1 definitions=2022-10-24_07,2022-10-21_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 adultscore=0 bulkscore=0 lowpriorityscore=0 mlxscore=0 spamscore=0 mlxlogscore=935 priorityscore=1501 suspectscore=0 phishscore=0 malwarescore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2209130000 definitions=main-2210240129 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC Hello, Labeled as RFC because I am unsure if adding Byte Queue Limits (BQL) is positively effecting the ibmveth driver. BQL is common among network drivers so I would like to incorporate it into the virtual ethernet driver, ibmveth. But I am having trouble measuring its effects. From my understanding (and please correct me if I am wrong), BQL will use the number of packets sent to the NIC to approximate the minimum number of packets to enqueue to a netdev_queue without starving the NIC. As a result, bufferbloat in the networking queues are minimized which may allow for smaller latencies. After performing various netperf tests under differing loads and priorities, I do not see any performance effect when comparing the driver with and without BQL. The ibmveth driver is a virtual driver which has an abstracted view of the NIC so I am comfortable without seeing any performance deltas. That being said, I would like to know if BQL is actually being enforced in some way. In other words, I would like to observe a change in the number of queued bytes during BQL implementations. Does anyone know of a mechanism to measure the length of a netdev_queue? I tried creating a BPF script[1] to track the bytes in a netdev_queue but again am not seeing any difference with and without BQL. I do not believe anything is wrong with BQL (it is more likely that my tracing is bad) but I would like to have some evidence of BQL having a positive effect on the device. Any recommendations or advice would be greatly appreciated. Thanks. [1] https://github.com/nick-child-ibm/bpf_scripts/blob/main/bpftrace_queued_bytes.bt Nick Child (1): ibmveth: Implement BQL drivers/net/ethernet/ibm/ibmveth.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)