Return-Path: Received: from smtp5-g21.free.fr ([212.27.42.5]:46806 "EHLO smtp5-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752795AbZICNji (ORCPT ); Thu, 3 Sep 2009 09:39:38 -0400 Message-ID: <4A9FC719.9020104@corp.free.fr> Date: Thu, 03 Sep 2009 15:39:37 +0200 From: Yohan To: Trond Myklebust CC: Andrew Morton , linux-kernel@vger.kernel.org, linux-nfs@vger.kernel.org, Neil Brown , "J. Bruce Fields" , mikevs@xs4all.net Subject: Re: VM issue causing high CPU loads References: <4A92A25A.4050608@yohan.staff.proxad.net> <20090824162155.ce323f08.akpm@linux-foundation.org> <4A96463E.5080002@corp.free.fr> <4A9C34F8.2010307@corp.free.fr> <20090902170642.f4381c1d.akpm@linux-foundation.org> <1251982884.18338.9.camel@heimdal.trondhjem.org> In-Reply-To: <1251982884.18338.9.camel@heimdal.trondhjem.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 >>> I did only: >>> >>> --- linux-2.6.27.21/include/linux/sunrpc/auth.h 2009-03-23 23:04:09.000000000 +0100 >>> +++ linux-2.6.27.21/include/linux/sunrpc/auth.h 2009-05-19 16:02:35.000000000 +0200 >>> @@ -62,8 +62,12 @@ >>> */ >>> - #define RPC_CREDCACHE_HASHBITS 4 >>> + #define RPC_CREDCACHE_HASHBITS 12 >>> >>> >>> And i test it in prod since sunday: i only have 36% of one core used by >>> system >>> versus more than 3 cores used by system in another server that did a >>> drop_caches at morning... >>> >> OK, but it's still pretty bad. Let's tell the NFS guys. >> >> In http://bugzilla.kernel.org/show_bug.cgi?id=14024 we appear to have a >> major meltdown caused by the linear search in >> rpcauth_lookup_credcache() with Yohan's workload. >> > OK. Could we please have some more details about the actual workload involved here? > I add a new server CPU graph and 60s readprofile on the bugzilla > As far as I can see, there is no RPCSEC_GSS involved, so credentials > should never expire. They will be reused as long as processes aren't > switching between thousands and thousands of different combinations of > uid, gid and groups. My servers are imap servers. Foreach user (~15 million) it have a specific uid over ~10 nfs netapp storage.