Messages in this thread |  | | | Date | Thu, 2 Nov 2006 09:27:40 +0000 | | From | "Daniel J Blueman" <> | | Subject | Re: How to optimize system time for such case? |
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On 02/11/06, miles <zhfeng.osprey@gmail.com> wrote: > On 11/2/06, Daniel J Blueman <daniel.blueman@gmail.com> 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/
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