Return-Path: Received: from mail-yk0-f179.google.com ([209.85.160.179]:36501 "EHLO mail-yk0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751963AbbCZQGv (ORCPT ); Thu, 26 Mar 2015 12:06:51 -0400 Received: by ykcn8 with SMTP id n8so29988605ykc.3 for ; Thu, 26 Mar 2015 09:06:50 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <551429F7.5050305@Netapp.com> References: <20150319153627.GA20852@fieldses.org> <20150320151718.GD2036@fieldses.org> <20150320162303.GA18786@infradead.org> <20150320182621.GH2036@fieldses.org> <20150324174916.GA28906@infradead.org> <55142405.3090000@Netapp.com> <20150326153848.GB30482@fieldses.org> <551429F7.5050305@Netapp.com> Date: Thu, 26 Mar 2015 12:06:50 -0400 Message-ID: Subject: Re: [PATCH v3 3/3] NFSD: Add support for encoding multiple segments From: Trond Myklebust To: Anna Schumaker Cc: "J. Bruce Fields" , Christoph Hellwig , Marc Eshel , "linux-nfs@vger.kernel.org" , linux-nfs-owner@vger.kernel.org, xfs@oss.sgi.com Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, Mar 26, 2015 at 11:47 AM, Anna Schumaker wrote: > On 03/26/2015 11:38 AM, J. Bruce Fields wrote: >> On Thu, Mar 26, 2015 at 11:32:25AM -0400, Trond Myklebust wrote: >>> On Thu, Mar 26, 2015 at 11:21 AM, Anna Schumaker >>> wrote: >>>> Here are my updated numbers! I tested with files 5G in size: one 100% data, one 100% hole, and one alternating between hole and data every 4K. I collected data for both v4.1 and v4.2 with and without the READ_PLUS patches: >>>> >>>> ########################## >>>> # # >>>> # Without READ_PLUS # >>>> # # >>>> ########################## >>>> >>>> >>>> NFS v4.1: >>>> Trial >>>> |---------|---------|---------|---------|---------|---------|---------| >>>> | | 1 | 2 | 3 | 4 | 5 | Average | >>>> |---------|---------|---------|---------|---------|---------|---------| >>>> | Data | 8.723s | 7.243s | 8.252s | 6.997s | 6.980s | 7.639s | >>>> | Hole | 5.271s | 5.224s | 5.060s | 4.897s | 5.321s | 5.155s | >>>> | Mixed | 8.050s | 10.057s | 7.919s | 8.060s | 9.557s | 8.729s | >>>> |---------|---------|---------|---------|---------|---------|---------| >>>> >>>> >>>> >>>> >>>> NFS v4.2: >>>> Trial >>>> |---------|---------|---------|---------|---------|---------|---------| >>>> | | 1 | 2 | 3 | 4 | 5 | Average | >>>> |---------|---------|---------|---------|---------|---------|---------| >>>> | Data | 6.707s | 7.070s | 6.722s | 6.761s | 6.810s | 6.814s | >>>> | Hole | 5.152s | 5.149s | 5.213s | 5.206s | 5.312s | 5.206s | >>>> | Mixed | 7.979s | 7.985s | 8.177s | 7.772s | 8.280s | 8.039s | >>>> |---------|---------|---------|---------|---------|---------|---------| >>>> >>>> >>>> >>>> >>>> >>>> ####################### >>>> # # >>>> # With READ_PLUS # >>>> # # >>>> ####################### >>>> >>>> >>>> NFS v4.1: >>>> Trial >>>> |---------|---------|---------|---------|---------|---------|---------| >>>> | | 1 | 2 | 3 | 4 | 5 | Average | >>>> |---------|---------|---------|---------|---------|---------|---------| >>>> | Data | 9.082s | 7.008s | 7.116s | 6.771s | 7.902s | 7.576s | >>>> | Hole | 5.333s | 5.358s | 5.380s | 5.161s | 5.282s | 5.303s | >>>> | Mixed | 8.189s | 8.308s | 9.540s | 7.937s | 8.420s | 8.479s | >>>> |---------|---------|---------|---------|---------|---------|---------| >>>> >>>> >>>> >>>> >>>> NFS v4.2: >>>> Trial >>>> |---------|---------|---------|---------|---------|---------|---------| >>>> | | 1 | 2 | 3 | 4 | 5 | Average | >>>> |---------|---------|---------|---------|---------|---------|---------| >>>> | Data | 7.033s | 6.829s | 7.025s | 6.873s | 7.134s | 6.979s | >>>> | Hole | 1.794s | 1.800s | 1.905s | 1.811s | 1.725s | 1.807s | >>>> | Mixed | 7.590s | 8.777s | 9.423s | 10.366s | 8.024s | 8.836s | >>>> |---------|---------|---------|---------|---------|---------|---------| >>>> >>> >>> So there is a clear win in the 100% hole case here, but otherwise the >>> statistical fluctuations are dominating the numbers. Can you get us a >>> little more stats and then perhaps run the results through nfsometer? >> >> Also, could you describe the setup (are these still kvm's), and how >> you're clearing the cache between runs? > > These are still KVMs and my server is exporting an xfs filesystem. I clear caches by running "echo 3 > /proc/sys/vm/drop_caches" on the server before every read, and I remount my client after reading each set of three files once. I agree that you have to use the 'drop_caches' interface on the server, but why not just use O_DIRECT on the clients? -- Trond Myklebust Linux NFS client maintainer, PrimaryData trond.myklebust@primarydata.com