Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752768AbWKBJ1n (ORCPT ); Thu, 2 Nov 2006 04:27:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752769AbWKBJ1m (ORCPT ); Thu, 2 Nov 2006 04:27:42 -0500 Received: from ug-out-1314.google.com ([66.249.92.174]:6078 "EHLO ug-out-1314.google.com") by vger.kernel.org with ESMTP id S1752768AbWKBJ1m (ORCPT ); Thu, 2 Nov 2006 04:27:42 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=gOiSfcO+d2Rko0KCDzVrn1dyTmwmV1orkAs/Fra46BARw6ix/VdugRDjWNrSfUV+jb82T37o91MQVSmFQ1t3c0qMvylP0dNNmjSEiokiP0zmKwckbe4LhQu9JsNQJHnRez1G48ruZuuEN4tbfKgPFtr0Yo1nraJPhStNmlBsk8Q= Message-ID: <6278d2220611020127j62f94ccat5a158059feab37cb@mail.gmail.com> Date: Thu, 2 Nov 2006 09:27:40 +0000 From: "Daniel J Blueman" To: zhfeng.osprey@gmail.com Subject: Re: How to optimize system time for such case? Cc: "Linux Kernel" In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <6278d2220611020110m34d09673yee73edd6c0c86ff@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1876 Lines: 38 On 02/11/06, miles wrote: > On 11/2/06, Daniel J Blueman wrote: > > FENG ZHOU wrote: > > > Hello, all > > > I am optimizing a compiler and I believe there is a bug in such > > > compile. Currently, I have a test case, which is a scientific > > > application, has a lot of system time. This is weird, because this > > > case does not have many system calls. Meanwhile, compiled at another > > > option, I found all the "system time" are gone! So, I assume there is > > > some problem in the first one (though both binary produce correct > > > result). I used some performance tuning tool and found the hottest > > > address for CPU privilege level change event is: 0xa000000100001a70. > > > This address is not in code or data segment. Now, I am kinda stuck > > > here. My question is: how to find what this address is? Or find out > > > what is the cause of the "system time"? Thanks in advance. > > > > > > PS: the platform is Itanium 2. > > > -Feng > > > > First question is what kernel, second is how much memory? > > > > I recently had this experience (high system time) with some vendor > > kernels with a system with 16GB of memory and 4-8GB processes. The VM > > was trying to reclaim pages like crazy, but failing. > > The system is a debian3.1 with 2.6.8 #1 SMP kernel. The total memory is 4GB. > Total number of processes is about 100. It is a SPEC CPU program. I'd say it's worth a shot with a more modern kernel. There are probably related bugs in that kernel. The one I had (related, but not directly) problems with was 2.6.9 + vendor patches. -- Daniel J Blueman - 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/