Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755488AbZICOI5 (ORCPT ); Thu, 3 Sep 2009 10:08:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755237AbZICOI5 (ORCPT ); Thu, 3 Sep 2009 10:08:57 -0400 Received: from smtp5-g21.free.fr ([212.27.42.5]:44519 "EHLO smtp5-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755078AbZICOI4 (ORCPT ); Thu, 3 Sep 2009 10:08:56 -0400 Message-ID: <4A9FCDF7.1090700@corp.free.fr> Date: Thu, 03 Sep 2009 16:08:55 +0200 From: Yohan User-Agent: Thunderbird 2.0.0.22 (Windows/20090605) MIME-Version: 1.0 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> <4A9FC719.9020104@corp.free.fr> <1251986526.18338.29.camel@heimdal.trondhjem.org> In-Reply-To: <1251986526.18338.29.camel@heimdal.trondhjem.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1142 Lines: 27 Trond Myklebust wrote: > On Thu, 2009-09-03 at 15:39 +0200, Yohan wrote: > >>> 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. >> > OK, so 16 hash buckets are likely to be filled with ~10^6 entries each. > I can see that might be a performance issue... > > So afaics, you did try adjusting the hashtable size. How much larger > does it have to be before you start to get acceptable performance? If it > solves your problem we could make hash table sizes adjustable via a > module parameter, for instance. > I run now with a value of 12, and it's great for me... -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/