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=-2.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS,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 ABA94C43387 for ; Thu, 27 Dec 2018 22:34:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6CA392148E for ; Thu, 27 Dec 2018 22:34:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="YV83CEd9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730058AbeL0Wet (ORCPT ); Thu, 27 Dec 2018 17:34:49 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:39454 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729908AbeL0Wet (ORCPT ); Thu, 27 Dec 2018 17:34:49 -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 wBRMTu8Z075620; Thu, 27 Dec 2018 22:34:46 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=tSbbs4sazqv5WJ/mlvGMZYdkey3cKT9s4DZGHiDo6dQ=; b=YV83CEd9OKzqh5gwc55YDBcQcR6PznVSmYA9UUHlGm2Ct6kAQT7kEnYJ4aWipeKH2HsS pSME7KkYA9sJAt21E25l0iKCYWEla8XvPmIWXywacrVqOtKi+allzTBVeoxb7AObj53U ncFZ5zgc1OOt21emITTxF/SIMYH+g+RvPRuS9yIKm5w5GEtxmz3URcMX3ZAaREbjGbtJ DY+pDGSSqgscDEWCx5QBUBX1HdPJXYpy7+ay0asf8WXLa3b5GFh2J3GXb0e1MyCDUsks unVA2hoHdPiOiLJ3KIMlIh/Y2nf7Y8qUy+vxbU0z9kWBsr5C1u3aJ0e7CbL9wQeHW86M ow== Received: from userv0022.oracle.com (userv0022.oracle.com [156.151.31.74]) by userp2130.oracle.com with ESMTP id 2phcptxsfc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 27 Dec 2018 22:34:46 +0000 Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userv0022.oracle.com (8.14.4/8.14.4) with ESMTP id wBRMYjde012462 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 27 Dec 2018 22:34:46 GMT Received: from abhmp0019.oracle.com (abhmp0019.oracle.com [141.146.116.25]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id wBRMYjLA025768; Thu, 27 Dec 2018 22:34:45 GMT Received: from [192.168.1.184] (/68.61.232.219) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 27 Dec 2018 14:34:45 -0800 Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (1.0) Subject: Re: [PATCH v3 26/44] SUNRPC: Improve latency for interactive tasks From: Chuck Lever X-Mailer: iPad Mail (16C50) In-Reply-To: Date: Thu, 27 Dec 2018 17:34:42 -0500 Cc: Linux NFS Mailing List Content-Transfer-Encoding: quoted-printable Message-Id: <4FB643C8-4790-42B9-AF38-622E10F6A1B2@oracle.com> References: <20180917130335.112832-1-trond.myklebust@hammerspace.com> <20180917130335.112832-2-trond.myklebust@hammerspace.com> <20180917130335.112832-3-trond.myklebust@hammerspace.com> <20180917130335.112832-4-trond.myklebust@hammerspace.com> <20180917130335.112832-5-trond.myklebust@hammerspace.com> <20180917130335.112832-6-trond.myklebust@hammerspace.com> <20180917130335.112832-7-trond.myklebust@hammerspace.com> <20180917130335.112832-8-trond.myklebust@hammerspace.com> <20180917130335.112832-9-trond.myklebust@hammerspace.com> <20180917130335.112832-10-trond.myklebust@hammerspace.com> <20180917130335.112832-11-trond.myklebust@hammerspace.com> <20180917130335.112832-12-trond.myklebust@hammerspace.com> <20180917130335.112832-13-trond.myklebust@hammerspace.com> <20180917130335.112832-14-trond.myklebust@hammerspace.com> <20180917130335.112832-15-trond.myklebust@hammerspace.com> <20180917130335.112832-16-trond.myklebust@hammerspace.com> <20180917130335.112832-17-trond.myklebust@! hammerspace.com> <20180917130335.112832-18-trond.myklebust@hammerspace.com> <20180917130335.112832-19-trond.myklebust@hammerspace.com> <20180917130335.112832-20-trond.myklebust@hammerspace.com> <20180917130335.112832-21-trond.myklebust@hammerspace.com> <20180917130335.112832-22-trond.myklebust@hammerspace.com> <20180917130335.112832-23-trond.myklebust@hammerspace.com> <20180917130335.112832-24-trond.myklebust@hammerspace.com> <20180917130335.112832-25-trond.myklebust@hammerspace.com> <20180917130335.112832-26-trond.myklebust@hammerspace.com> <20180917130335.112832-27-trond.myklebust@hammerspace.com> <4D3465FB-041C-4BB1-AB75-03511FA5AAF1@oracle.com> To: Trond Myklebust X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9119 signatures=668680 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=359 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1812270194 Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org > On Dec 27, 2018, at 5:14 PM, Trond Myklebust wro= te: >=20 >=20 >=20 >> On Dec 27, 2018, at 20:21, Chuck Lever wrote: >>=20 >> Hi Trond- >>=20 >> I've chased down a couple of remaining regressions with the v4.20 NFS cli= ent, >> and they seem to be rooted in this commit. >>=20 >> When using sec=3Dkrb5, krb5i, or krb5p I found that multi-threaded worklo= ads >> trigger a lot of server-side disconnects. This is with TCP and RDMA trans= ports. >> An instrumented server shows that the client is under-running the GSS seq= uence >> number window. I monitored the order in which GSS sequence numbers appear= on >> the wire, and after this commit, the sequence numbers are wildly misorder= ed. >> If I revert the hunk in xprt_request_enqueue_transmit, the problem goes a= way. >>=20 >> I also found that reverting that hunk results in a 3-4% improvement in fi= o >> IOPS rates, as well as improvement in average and maximum latency as repo= rted >> by fio. >>=20 >=20 > Hmm=E2=80=A6 Provided the sequence numbers still lie within the window, th= en why would the order matter? The misordering is so bad that one request is delayed long enough to fall outside the window. The new =E2=80=9Cneed re-encode=E2=80=9D logic does= not trigger. > Cheers > Trond >=20 >=20 > _________________________________ > Trond Myklebust > Linux NFS client maintainer, Hammerspace > trond.myklebust@hammerspace.com >=20