[aklug] Re: Gotta get me an i7

On Mon, 29 Mar 2010, Joshua J. Kugler wrote:

> On Monday 29 March 2010, Christopher Howard elucidated thus:
>> Joshua J. Kugler wrote:
>>> On Monday 29 March 2010, Christopher Howard elucidated thus:
>>>> So, at work I'm setting up a Gentoo system on an HP with an i7
>>>> processor (with eight virtual cores). I passed in -j7 as a make
>>>> option, and it built the whole bloody kernel, modules and
>>>> everything, in five minutes. Sweetness.
>>>
>>> Five? Wow...I seem to remember Linus T. bragging back in the day
>>> that his four processor system (this was when multi-CPU systems,
>>> especially
>>>
>>>> 2, were especially rare) only took 2.5 minutes. Must be seriously
>>>
>>> I/O bound.
>>>
>>> Can I find a citation for that? No...just going off memory.
>>>
>>> j
>>
>> Really? Guess I'm just used to the hour/two-hour jobs on all my old
>> dual-cores and Pentium IIIs at home. I only passed in the -j7
>> makeopt... probably could have tweaked it more.
>
> Actually, the supposed optimal number is num_cores+1, so you should
> pass -j8 :)
>
>> Of course, there probably wasn't quite as much source code to build
>> back then...
>
> Right, 2.5 minutes back then, 5 minutes now...serious code growth.
> Hmm...did you compile *all* the modules? That would add some serious
> time as device support has grown by leaps and bounds. If you only
> compiled the drivers for your machine (i.e. only the needed modules or
> a monolithic kernel) then it would probably be REALLY fast.
>
> j

There is a large I/O factor here. I remember clocking 2.4 kernel builds
at 2 min 35 sec on a dual PIII 500, but this system had a hardware raid
array of 10k cheetas.

Last time I looked, the build time for recent 2.6 was ranging from just
under 2 to a little under 3 minutes on my quad 2Ghz opteron, and it was
totally I/O limited.

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Received on Tue Mar 30 12:24:04 2010