# Intel Core 2 Duo MAKEOPTS?

## _Leprechaun_

The Gentoo Handbook says this:

 *Quote:*   

> 
> 
> With MAKEOPTS you define how many parallel compilations should occur when you install a package. A good choice is the number of CPUs in your system plus one, but this guideline isn't always perfect.
> 
> Code Listing 14: MAKEOPTS for a regular, 1-CPU system:
> ...

 

If I have an Intel Core 2 Duo (using i686 *.iso) would I be considered to have "2" CPUs? So would I use: MAKEOPTS="-j3"?

Thanks.   :Smile: 

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## hans0r

yes

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## _Leprechaun_

Okay, thanks!

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## thunder

Well i would say -j5 compilation will be a bit faster.

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## BlackLodge

 *Quote:*   

> Well i would say -j5 compilation will be a bit faster

 

Is -j5 safe for a normal 'desktop' user?

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## John R. Graham

Those are thumb rules.  The goal is to keep the CPU cores from being idle.  You could start out at "-j3" and then use your favorite CPU monitor (I just use "top") to see if your CPU cores are fully occupied.  If they're not, then increase the number until they are.  For maximum performance, you want to be on the cusp.

It's not a question of being "safe".  More processes means more overhead, that's all.  You want to minimize the overhead while maximizing the CPU core usage.

- John

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## Veldrin

 *Quote:*   

> It's not a question of being "safe". More processes means more overhead, that's all. You want to minimize the overhead while maximizing the CPU core usage. 

  And the more processes are running the more RAM you need.

I currently use MAKEOPTS="-j4" on a Santa-Rosa Notebook.

 *Quote:*   

> If I have an Intel Core 2 Duo (using i686 *.iso) would I be considered to have "2" CPUs? So would I use: MAKEOPTS="-j3"? 

  Some even that makeopts should be somewhere #cores+1 to 2*#cores. "Worst Case Scenario": every single core, finishes its job at the same time, and every single one requests a new one jobs. That's why there is a "spare" job for every core. In the other case, you might have to wait until a new job is created...

just my .02$

V.

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## barophobia

If you are adventurous you can just "-j" with out any arguments so there will be no limit on the number of processes.  Will bring down all but the best machines, since it is kind of like a fork bomb you are doing though "controlled".

Anyways I just -j3 on my santa-rosa

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## d2_racing

I have a Intel Core 2 T7200 and I use -j3

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## razze

I am running a AMD X2, and use MAKEOPTS="-j5". According to gkrellm it keeps both the cores nice and busy during compiles! I at one point did some testing on compiling the kernel using different -j -values, and came to the conclusion that as long as j > 1 the difference is not really noticeable. The times kept decreasing up to around -6, but after that the overhead increased and the compile times got longer again.

razze

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