Return-Path: Received: from tamar.safe-mail.net ([212.29.227.229]:35656 "EHLO tamar.safe-mail.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752438AbbHEOGt (ORCPT ); Wed, 5 Aug 2015 10:06:49 -0400 Received: by tamar.safe-mail.net with Safe-mail (Exim 4.66) (envelope-from ) id 1ZMwdy-0007Ty-S2 for linux-nfs@vger.kernel.org; Wed, 05 Aug 2015 07:13:58 -0400 Subject: extremely slow v4 performance on gigabit link Date: Wed, 5 Aug 2015 07:13:58 -0400 From: jhopper@Safe-mail.net To: linux-nfs@vger.kernel.org Message-Id: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-nfs-owner@vger.kernel.org List-ID: I have a very slow (less than 1MB/s) performance with nfsv4 TCP, rsize/wsize have no effect, server is a kernel 3.19 x86 100hz no preempt exporting async nfsv4 TCP on nfs-utils 1.2.7, client is a kernel 4.1.3 x64 1000hz full preempt with nfs-utils 1.3.2 , physical link is 1 gigabit full duplex, I mounted a few cifs shares to check, the cifs shares are working at 30 MB/s and higher is it possible that preempt has an effect on NFS performance ? does timeslice have effect on performance ?