hi, Thomas Trepl,

Thank you very much for you reply. I have some questions about
your comments below in the text.

Thomas Trepl wrote:
> On Sunday 23 March 2008 03:44:59 Zhiming Wu wrote:
>   
>> Hi, all guys.
>> Maybe this question should not be posted here, but if any
>> one of you have experience on this, please give me some advice.
>> I have built a LFS+BLFS system on a IA32(Pentium M) computer
>> and it runs fine. Now I also want to LFS+BLFS on another
>> computer with Pentium D 945 CPU with two cores. I have tried
>> to copy what I built on Pentium M computer to the Pentium D
>> computer with a little modification(make it bootable on that
>> computer), and it was able to work. But I could only see one
>> core from /proc/cpuinfo. My questions are:
>> 1. If I use this system in this way, is it true that only half
>> of the Pentium D CPU is working?
>>     
> No its not. Only the kernel may be compiled only for only one CPU (not a 
> SMP-kernel) but thats not that dramatically. Simply recompile the kernel with 
> the Multiprocessor option switched on.
>   

By "Multiprocessor option", do you mean "SMP" option?

>> What is the performance in this 
>> situation, comparing to the situation using x86_64 architecture?
>> 2. If I want both of two cores to work, is it necessary for me
>> to rebuild the LFS+BLFS from scratch using x86_64 architecture?
>> Or only need I rebuild the kernel?
>>     
> Rebuild the kernel and you're fine.  On desktop systems, having more CPUs 
> does 
> not immediatly lead to a faster system if the application programs do not 
> support multi-threading for CPU intensive operations well.  One CPU will be 
> used to 100%, the other(s) does nothing. As far as I know, you do not need to 
> recompile any application program - either they do support threads or they 
> don't.
>   

If I want to make two tasks be able to run on two cores at the same 
time, is there a
approach to achieve this? Such as:
- Turn on the "SMP" option for the kernel.
- Select x86_64 architecture when compiling the kernel.
- Make application be capable of multi-threading when building them. 
(How to do this?
Is this very complex because each application has its own way?)

Thanks,

Best Regargs,
Zhiming Wu
>> Best Regargs,
>> Zhiming Wu
>>     
>
> --
> Thomas
>   

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