Return-Path: Received: from mx143.netapp.com ([216.240.21.24]:17257 "EHLO mx143.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760270AbbIDTHZ (ORCPT ); Fri, 4 Sep 2015 15:07:25 -0400 From: Anna Schumaker To: CC: Subject: [PATCH v1 0/3] NFSD: Add READ_PLUS support Date: Fri, 4 Sep 2015 15:07:18 -0400 Message-ID: <1441393641-30152-1-git-send-email-Anna.Schumaker@Netapp.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-nfs-owner@vger.kernel.org List-ID: This is an updated posting of my NFS v4.2 READ_PLUS patches from several months ago, and it should apply against current development trees. I tested this code using dd to read a file between two KVMs, and I compared the reported transfer rates against various NFS versions and the local XFS filesystem. I tested using four 5 GB files, the first two simply entirely data or entirely hole. The others alternate between data and hole pages, at either 4 KB (one page) or 8 KB (two page) intervals. I found that dd uses a default block size of 512 bytes, which could cause reads over NFS to take forever. I bumped this up to 128K during my testing by passing the argument "bs=128K" to dd. My results are below: | XFS | NFS v3 | NFS v4.0 | NFS v4.1 | NFS v4.2 -------|------------|------------|------------|------------|------------ Data | 2.7 GB/s | 845 MB/s | 864 MB/s | 847 MB/s | 807 MB/s Hole | 4.1 GB/s | 980 MB/s | 1.1 GB/s | 989 MB/s | 2.3 GB/s 1 Page | 1.6 GB/s | 681 MB/s | 683 MB/s | 688 MB/s | 672 MB/s 2 Page | 2.5 GB/s | 760 MB/s | 760 MB/s | 755 MB/s | 836 MB/s The pure data case is slightly slower on NFS v4.2, most likely due to additional server-side lseeks while reading. The alternating 1 page regions test didn't see as large a slowdown, most likely because of to the additional savings by not transferring zeroes over the wire. Any slowdown caused by additional seeks is more than made up for by the time we reach 2 page intervals. These patches and the corresponding client changes are available in the [read_plus] branch of git://git.linux-nfs.org/projects/anna/linux-nfs.git Questions? Comments? Thoughts? Anna Anna Schumaker (3): NFSD: nfsd4_encode_read{v}() should encode eof and maxcount NFSD: Add basic READ_PLUS support NFSD: Add support for encoding multiple segments fs/nfsd/nfs4proc.c | 16 +++++ fs/nfsd/nfs4xdr.c | 183 ++++++++++++++++++++++++++++++++++++++++++----------- 2 files changed, 161 insertions(+), 38 deletions(-) -- 2.5.1