Re: [gentoo-user] Problems with MAKEOPTS -j

[Michael Mol <mikemol@gmail.com>]

On Thu, Aug 25, 2011 at 9:16 AM, Dale <rdalek1967@gmail.com> wrote:
> Michael Mol wrote:
>>
>> Sometimes. My understanding is that it comes from packages which are
>> badly constructed, and can't reliably handle parallel builds. I'm told
>> that these cases are bugs and should be reported. Sometimes, if I
>> watch build output fly by, I'll even see something like
>>
>> make -j10 -j1 (some target name)
>>
>> where a maintainer decided to put an overriding -j1 after MAKEOPTS.
>>
>>
>> About two years ago, I found that, on my system (quad-core AMD Phenom
>> 9650), -j8 resulted in the fastest build time, as measured by building
>> ffmpeg.[1] Currently, I'm running -j10, and that's because I've been
>> using distcc to pass a couple compile tasks off to other systems.
>> (Though with the box I was deferring to scrapped for parts, I'll drop
>> this down to -j8 again)
>>
>> [1] Tested by building in tmpfs. You can find my data here:
>>
>> http://multimedia.cx/eggs/ffmpeg-and-multiple-build-threads/#comment-150325
>>
>>
>
> This is interesting.  I changed mine to j8 too.  See how this works.  CPUs
> are so fast nowadays, they can do a lot pretty fast.  I'm trying to imagine
> 10 years from now.  O_O

I imagine there's a *lot* of money to be made researching AST
optimization and simplification transform searches as delegated to
GPUs. I don't imagine it'll speed up compiling much, but I do imagine
the resulting optimized programs will run far faster.  Especially if
there's a trend toward declarative programming languages. (I wonder if
there's a Prolog implementation that dispatches work to OpenCL. I'm
surprised the Mozart/Oz folks haven't dug in that direction yet.)

-- 
:wq