From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from moutng.kundenserver.de (moutng.kundenserver.de [212.227.126.171]) by ozlabs.org (Postfix) with ESMTP id AC5E6DE3C7 for ; Tue, 15 Jul 2008 06:44:14 +1000 (EST) From: Arnd Bergmann To: linuxppc-dev@ozlabs.org Subject: Re: 82xx performance Date: Mon, 14 Jul 2008 22:44:07 +0200 References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Message-Id: <200807142244.07450.arnd@arndb.de> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Monday 14 July 2008, Rune Torgersen wrote: > Context switching - times in microseconds - smaller is better > ------------------------------------------------------------------------ > Host OS 2p/0K 2p/16K 2p/64K 8p/16K 8p/64K 16p/16K 16p/64K > ctxsw ctxsw ctxsw ctxsw ctxsw ctxsw ctxsw > --------- ------------- ------ ------ ------ ------ ------ ------- ------- > 9919_unit Linux 2.6.25 20.6 86.2 28.5 103.8 38.7 111.8 57.4 > 9919_unit Linux 2.6.18 5.3300 63.2 17.9 73.4 23.1 74.9 26.2 This is certainly significant, but a lot has happened between the two versions. I few ideas: * compare some of the key configuration options: # CONFIG_DEBUG_* # CONFIG_PREEMPT* # CONFIG_NO_HZ # CONFIG_HZ * Try looking at where the time is spent, using oprofile or readprofile * Try setting /proc/sys/kernel/compat/sched_yield to 1, to get the legacy behaviour of the scheduler. * Maybe there is a kernel version that supports your hardware in both arch/ppc/ and arch/powerpc. In that case, you could see if the platform change had an impact. Arnd <><