make -j$n buildworld : use of -j investigated

[Rob]

Nick Barnes wrote:
> On Thu, 25 Nov 2004 16:19:02 +0900, Rob <spamrefuse at yahoo.com> wrote:
> 
> 
>>>     time(minutes) * speed(MHz) * nproc / 1000 MHz
> 
> 
> Looking at your examples, it seems you divide by 1e5, not by 1000.

Sorry, yes you're right.

> In other words, buildworld is CPU bound and takes about 6e12 clock
> cycles.  Use -j<nproc>.

My main point is: when using "-j<nproc>", I am able to predict how long
the buildworld takes on a range of 'mainstream' systems like the ones I
have (pentium-II to pentium-IV and dual-pentium-III):

     time(minutes) = 1e5 / ( speed(MHz) * nproc )

P-II    333 MHz : 300 min.
P-III   700 MHz : 142 min.
P-III 2x800 MHz :  62 min.
P-IV   2000 MHz :  50 min.

Within a few minutes, all these times are correct.

I still have to test my P-I/150 MHz also running 5.3, and verify
that buildworld will take approx. 670 min.

Rob.