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Subject: Re: How to get more VPU time.

Author: David Blackman

Date: 22:08:59 04/08/99

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On April 08, 1999 at 13:16:53, José de Jesús García Ruvalcaba wrote:

>On April 08, 1999 at 08:12:09, David Blackman wrote:
>
>>Do these cpu figures include both user and system cpu time for the program, or
>>just user time? If the program is burning lots of system time, maybe you have a
>>problem with un-aligned memory accesses being trapped and emulated in the
>>kernel.
>
>	It is only user time. How do I check for un-aligned memory accesses?
>Thanks for your answer.

If it is just normal C code, there shouldn't be any. But if you do stuff like

char a[10000];
int *b;
b=(int *)a;

then it might happen. Actually, there are a few other things could cause kernel
trap emulation on Sparc. The architecture has changed a few times, especially
for things like integer multiply and divide. Try to tell the compiler exactly
what version of the Sparc architecture you have. It is definately bad if the
compiler is producing code for a newer version than what you have.

There are other possibilities too. If the program is reasonably small and well
written, i might be able to tell by looking at it. Is it available somewhere?



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