Re: [gentoo-amd64] MAKEOPTS values for Athlon 64 X2

[Toshinori Endo <endo.toshinori@gmail.com>]

Hello PaulNM,


PaulNM wrote:
> Hey folks,
>
>     I'm wondering if anyone has experimented with different values for 
> MAKEOPTS="-jx" on Athlon 64 X2's.  The guides usually suggest # of 
> cores/processors plus one. Looking at "man make.conf" doesn't help 
> much, it just says "Suggested settings are between CPUs+1 and  
> 2*CPUs+1". The only thing "man make" mentions about  the "-j" option 
> is "If the -j option is given without an argument, make  will  not 
> limit the number of jobs that can run simultaneously." I've also seen 
> some mentions of -j9 by people with dual core systems elsewhere, 
> indicating it drastically speed up some emerges.
>
>     So this leaves me with several possibilities. There's -j3 (current 
> setting), -j5, -j (no limit), -j9, or some other random number. Any 
> suggestions/warnings/links would be appreciated.
>
> Thanks,
>     PaulNM
>

On my 4x Dual-Core Opteron system, -j9 actually worked as expected, but 
not as much on the other system with two CPUs.

Is that what you want?

Here is the story.
The value of MAKEOPTS including -jx is passed to the `make' command so 
that x kid jobs at most can be executed.  If 1+#CPU is given as the 
parameter, each CPU is assigned a single kid process because make 
command itself does have much to do while the kids are working hard.  
Giving the larger number just let them do extra job to switch among kids 
in expense of performance down.

te
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