Return-Path: Received: from mail-ig0-f174.google.com ([209.85.213.174]:38598 "EHLO mail-ig0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755174AbbGCVKE (ORCPT ); Fri, 3 Jul 2015 17:10:04 -0400 Received: by igrv9 with SMTP id v9so83529367igr.1 for ; Fri, 03 Jul 2015 14:10:03 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1435877253-1497-1-git-send-email-mchen@cs.stonybrook.edu> Date: Fri, 3 Jul 2015 17:10:03 -0400 Message-ID: Subject: Re: [PATCH] nfs: avoid nfs_wait_on_seqid() for NFSv4.1 From: Ming Chen To: Trond Myklebust Cc: Linux NFS Mailing List , Linux FS-devel Mailing List , ezk@fsl.cs.stonybrook.edu Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: Glad that this is fixed. I just verified that in vanilla 4.1.1, NFSv4.1 is performing well with parallel opens. We found this problem in our benchmarking study using 3.14.17. In case you are interested, we wrote a paper about NFSv4.1 benchmarking: http://www.fsl.cs.sunysb.edu/docs/nfs4perf/nfs4perf-sigm15.pdf Thanks, Ming On Thu, Jul 2, 2015 at 7:23 PM, Trond Myklebust wrote: > On Thu, Jul 2, 2015 at 6:47 PM, Ming Chen wrote: >> >> seqid, introduced in NFSv4.0, requires state-changing operations be performed >> synchronously, and thus limits parallelism. NFSv4.1 supports "unlimited >> parallelism" by using sessions and slots; seqid is no longer used and must be >> ignored by NFSv4.1 server. However, the current nfs client always call >> nfs_wait_on_seqid() no matter the version is 4.0 or 4.1. > > Please see commit 63f5f796af613 ("NFSv4.1: Allow parallel > OPEN/OPEN_DOWNGRADE/CLOSE") which first appeared in Linux-4.0. > > Cheers > Trond