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=-1.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED 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 0F290C5CFFE for ; Tue, 11 Dec 2018 15:30:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C6E0D20672 for ; Tue, 11 Dec 2018 15:30:52 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="ui3xXhFk" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C6E0D20672 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nfs-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726916AbeLKPaw (ORCPT ); Tue, 11 Dec 2018 10:30:52 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:48818 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726417AbeLKPav (ORCPT ); Tue, 11 Dec 2018 10:30:51 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.22/8.16.0.22) with SMTP id wBBFSTnl098726; Tue, 11 Dec 2018 15:30:31 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=content-type : mime-version : subject : from : in-reply-to : date : cc : content-transfer-encoding : message-id : references : to; s=corp-2018-07-02; bh=dIq1VQ+LxT8riazWnuYugIHf6fGfMCwzGRVEAc2qezI=; b=ui3xXhFkuSrI2z+7C+0bPpO4ciR2LkODYhRcSm+K4AI5R7X//7uozM+ErIf2yJMuPKs5 o5FDmvEQS1hHLvYp/KIxtNzLDjxA/gyuOlAdag5yympxHBcbl5AXu2YDt4BfENfSrIZN NIPlstSODmBE8pp9emhHaJr8HYx1kYUdfubAPabbqYHZQNx4nrt2tzSUoBT6751S0YQP 4NdJI6JmpOpVcbR8ym/Jy+D6BivlFJdRtAWqRZbCXRFXdHox32ZU++nCKrDa+jpM0NFi mjBjSsvIXaSJUOSpTaEhhSCE65WIDh2jPugQXZQNQSzlLwEZhJ+QxBL06t7qZSYgiYzL uA== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by userp2130.oracle.com with ESMTP id 2p85cu4hwq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 11 Dec 2018 15:30:31 +0000 Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id wBBFUQHg027585 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 11 Dec 2018 15:30:26 GMT Received: from abhmp0016.oracle.com (abhmp0016.oracle.com [141.146.116.22]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id wBBFUPQO013247; Tue, 11 Dec 2018 15:30:26 GMT Received: from anon-dhcp-171.1015granger.net (/68.61.232.219) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 11 Dec 2018 07:30:25 -0800 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 11.5 \(3445.9.1\)) Subject: Re: [PATCH v3 05/24] xprtrdma: Reduce max_frwr_depth From: Chuck Lever In-Reply-To: <20181211140242.GC30471@infradead.org> Date: Tue, 11 Dec 2018 10:30:24 -0500 Cc: Anna Schumaker , linux-rdma@vger.kernel.org, Linux NFS Mailing List Content-Transfer-Encoding: 7bit Message-Id: <69E69F06-4B3C-4C91-9412-3E7FE14C2ADA@oracle.com> References: <20181210161723.4198.51071.stgit@manet.1015granger.net> <20181210162945.4198.24714.stgit@manet.1015granger.net> <20181211140242.GC30471@infradead.org> To: Christoph Hellwig X-Mailer: Apple Mail (2.3445.9.1) X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9103 signatures=668679 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=843 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1812110140 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org > On Dec 11, 2018, at 9:02 AM, Christoph Hellwig wrote: > > On Mon, Dec 10, 2018 at 11:29:45AM -0500, Chuck Lever wrote: >> Some devices advertise a large max_fast_reg_page_list_len >> capability, but perform optimally when MRs are significantly smaller >> than that depth -- probably when the MR itself is no larger than a >> page. >> >> By default, the RDMA R/W core API uses max_sge_rd as the maximum >> page depth for MRs. For some devices, the value of max_sge_rd is >> 1, which is also not optimal. Thus, when max_sge_rd is larger than >> 1, use that value. Otherwise use the value of the >> max_fast_reg_page_list_len attribute. >> >> I've tested this with a couple of devices, and it reproducibly >> improves the throughput of large I/Os by several percent. > > Can you list which devices for reference in the changelog? I have only three devices here. I can't make an exhaustive list. Besides, this is exactly how rdma_rw works. I thought this was common knowledge. -- Chuck Lever