From: Krishna Kumar2 Subject: Re: NFS performance degradation of local loopback FS. Date: Mon, 30 Jun 2008 15:40:30 +0530 Message-ID: References: <48652C24.6030409@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Cc: "J. Bruce Fields" , Benny Halevy , Chuck Lever , linux-nfs@vger.kernel.org, Peter Staubach To: Dean Hildebrand Return-path: Received: from e28smtp01.in.ibm.com ([59.145.155.1]:44812 "EHLO e28esmtp01.in.ibm.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755095AbYF3KLr (ORCPT ); Mon, 30 Jun 2008 06:11:47 -0400 Received: from d28relay04.in.ibm.com (d28relay04.in.ibm.com [9.184.220.61]) by e28esmtp01.in.ibm.com (8.13.1/8.13.1) with ESMTP id m5UABJLR031142 for ; Mon, 30 Jun 2008 15:41:19 +0530 Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay04.in.ibm.com (8.13.8/8.13.8/NCO v9.0) with ESMTP id m5UAAw8j1179822 for ; Mon, 30 Jun 2008 15:40:58 +0530 Received: from d28av05.in.ibm.com (loopback [127.0.0.1]) by d28av05.in.ibm.com (8.13.1/8.13.3) with ESMTP id m5UABIQS006269 for ; Mon, 30 Jun 2008 15:41:18 +0530 In-Reply-To: <48652C24.6030409@gmail.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: Dean Hildebrand wrote on 06/27/2008 11:36:28 PM: > One option might be to try using O_DIRECT if you are worried about > memory (although I would read/write in at least 1 MB at a time). I > would expect this to help at least a bit especially on reads. > > Also, check all the standard nfs tuning stuff, #nfsds, #rpc slots. > Since with a loopback you effectively have no latency, you would want to > ensure that neither the #nfsds or #rpc slots is a bottleneck (if either > one is too low, you will have a problem). One way to reduce the # of > requests and therefore require fewer nfsds/rpc_slots is to 'cat > /proc/mounts' to see your wsize/rsize. Ensure your wsize/rsize is a > decent size (~ 1MB). Number of nfsd: 64, and sunrpc.transports = sunrpc.udp_slot_table_entries = 128 sunrpc.tcp_slot_table_entries = 128 I am using: mount -o rw,bg,hard,nointr,proto=tcp,vers=3,rsize=65536,wsize=65536,timeo=600,noatime localhost:/local /nfs I have also tried with 1MB for both rsize/wsize and it didn't change the BW (other than mini variations). thanks, - KK