Return-Path: Received: from aserp1040.oracle.com ([141.146.126.69]:26927 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754989AbdFWUsh (ORCPT ); Fri, 23 Jun 2017 16:48:37 -0400 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Subject: Re: [PATCH RESEND 0/3] Improvements to page writeback commit policy From: Chuck Lever In-Reply-To: Date: Fri, 23 Jun 2017 16:48:31 -0400 Cc: Anna Schumaker , Linux NFS Mailing List Message-Id: <2062C819-C45A-4E8B-9222-78FB8270FB68@oracle.com> References: <20170620233539.22417-1-trond.myklebust@primarydata.com> To: Trond Myklebust Sender: linux-nfs-owner@vger.kernel.org List-ID: > On Jun 21, 2017, at 10:31 AM, Chuck Lever wrote: > >> >> On Jun 20, 2017, at 7:35 PM, Trond Myklebust wrote: >> >> The following patches are intended to smooth out the page writeback >> performance by ensuring that we commit the data earlier on the server. >> >> We assume that if something is starting writeback on the pages, then >> that process wants to commit the data as soon as possible, whether it >> is an application or just the background flush process. >> We also assume that for streaming type processes, we don't want to pause >> the I/O in order to commit, so we don't want to rely on a counter of >> in-flight I/O to the entire inode going to zero. >> >> We therefore set up a monitor that counts the number of in-flight >> writes for each call to nfs_writepages(). Once all the writes to that >> call to nfs_writepages has completed, we send the commit. Note that this >> mirrors the behaviour for O_DIRECT writes, where we similarly track the >> in-flight writes on a per-call basis. > > These are the same as the patches you sent May 16th? > I am trying to get a little time to try them out. After applying these four patches, I ran a series of iozone benchmarks with buffered and direct I/O. NFSv3 and NFSv4.0 on RDMA. Exports were tmpfs and xfs on NVMe. I see about a 10% improvement in buffered write throughput, no degradation elsewhere, and no crashes or other misbehav- ior. xfstests passes with the usual few failures. Buffered write throughput is still limited to 1GBps when targeting a tmpfs export on a 5.6GBps network. The server isn't breaking a sweat, but the client appears to be hit- ting some spin locks pretty hard. This is similar behavior to before the patches were applied. >> Trond Myklebust (3): >> NFS: Remove unused fields in the page I/O structures >> NFS: Ensure we commit after writeback is complete >> NFS: Fix commit policy for non-blocking calls to nfs_write_inode() >> >> fs/nfs/pagelist.c | 5 ++-- >> fs/nfs/write.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++- >> include/linux/nfs_page.h | 2 +- >> include/linux/nfs_xdr.h | 3 ++- >> 4 files changed, 64 insertions(+), 5 deletions(-) >> >> -- >> 2.9.4 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-nfs" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- > Chuck Lever > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Chuck Lever