Return-Path: Received: from mx.cs.uchicago.edu ([128.135.164.214]:56119 "EHLO mx.cs.uchicago.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933351AbdGKPjM (ORCPT ); Tue, 11 Jul 2017 11:39:12 -0400 Received: from localhost (localhost [127.0.0.1]) by mx.cs.uchicago.edu (Postfix) with ESMTP id 55D7C6076D for ; Tue, 11 Jul 2017 10:39:06 -0500 (CDT) Received: from mx.cs.uchicago.edu ([127.0.0.1]) by localhost (mx.cs.uchicago.edu [127.0.0.1]) (amavisd-new, port 10024) with LMTP id iFtxCljuNJJV for ; Tue, 11 Jul 2017 10:39:05 -0500 (CDT) Received: from [128.135.11.234] (hester2.cs.uchicago.edu [128.135.11.234]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx.cs.uchicago.edu (Postfix) with ESMTPSA id 81CD76070E for ; Tue, 11 Jul 2017 10:39:05 -0500 (CDT) Subject: Re: /etc/mtab read ~900 times by rpc.mountd To: linux-nfs@vger.kernel.org References: <8737a9x9ky.fsf@notabene.neil.brown.name> <595F1A3A.7070405@cs.uchicago.edu> <87efto69rs.fsf@notabene.neil.brown.name> <4ec2a8fc-3ca5-d26b-7742-be4e2f749c21@cs.uchicago.edu> <87y3rv4zrb.fsf@notabene.neil.brown.name> From: Phil Kauffman Message-ID: <1740081e-6180-1c88-0a0c-8747a92c65a1@cs.uchicago.edu> Date: Tue, 11 Jul 2017 10:39:05 -0500 MIME-Version: 1.0 In-Reply-To: <87y3rv4zrb.fsf@notabene.neil.brown.name> Content-Type: text/plain; charset=utf-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On 07/10/2017 06:51 PM, NeilBrown wrote: > This does look encouraging ... but I'm not sure we are comparing apples > with apples. I had a feeling this was the case. > Could you repeat your experiments after first running "exportfs -f" on > the nfs server? That should cause worst-case load on mountd. The new strace with '-tt': http://people.cs.uchicago.edu/~kauffman/nfs-kernel-server/test_with_patch_take2/2017-07-11_100929_strace.txt SSH test: http://people.cs.uchicago.edu/~kauffman/nfs-kernel-server/test_with_patch_take2/ssh_output.txt nfsserver# exportfs -f; m=$(pgrep rpc.mountd); strace -tt -p ${m} 2>&1 | tee `date +%F_%T`_strace.txt # cut -d' ' -f2 2017-07-11_100929_strace.txt| cut -d'(' -f1 | sort | uniq -c | sort -n 1 Process 73 select 143 write 216 close 216 fstat 216 open 48240 read 435599 stat 871162 statfs 871163 lstat > (and thanks for providing all the tracing details - I love getting > unambiguous data!!) No problem, I'm available to run any necessary tests. I also appreciate your help on this. -- Phil Kauffman Systems Admin Dept. of Computer Science University of Chicago kauffman@cs.uchicago.edu 773-702-3913