From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from netnation.com ([204.174.223.2]:57810 "EHLO peace.netnation.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1754431Ab0KIScn (ORCPT ); Tue, 9 Nov 2010 13:32:43 -0500 Received: from sim by peace.netnation.com with local (Exim 4.69) (envelope-from ) id 1PFszq-0000Fm-3a for linux-nfs@vger.kernel.org; Tue, 09 Nov 2010 10:32:42 -0800 Date: Tue, 9 Nov 2010 10:32:42 -0800 From: Simon Kirby To: linux-nfs@vger.kernel.org Subject: rpcauth_lookup_credcache hash size Message-ID: <20101109183242.GA29915@hostway.ca> Content-Type: text/plain; charset=us-ascii Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Hello! Just decided to run "perf top" on a web server which seemed to be CPU-bound and saw this at the top: samples pcnt function DSO _______ _____ ________________________ __________________ 5261.00 11.9% rpcauth_lookup_credcache [kernel.kallsyms] 2429.00 5.5% lex_scan php4 2184.00 5.0% thread_group_cputime [kernel.kallsyms] 1505.00 3.4% established_get_next [kernel.kallsyms] 1083.00 2.5% zendparse php4 1055.00 2.4% zend_hash_find php4 958.00 2.2% lex_scan php5 905.00 2.1% execute php4 890.00 2.0% memcpy /lib/libc-2.7.so I see this just became configurable, but probably 4 bits (16 buckets?) is probably a bit small for the default, no? (hlist_head is just a pointer, 4 or 8 bytes per bucket, so the default is 128 bytes on x64 :)) I guess it really needs to auto-scale... Simon-