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Date: Thu, 25 Nov 2004 18:52:51 -0800
From: Kris Kennaway <kris@obsecurity.org>
To: Rob <spamrefuse@yahoo.com>
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Subject: Re: make -j$n buildworld : use of -j   investigated
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On Fri, Nov 26, 2004 at 11:44:53AM +0900, Rob wrote:
> Nick Barnes wrote:
> >On Thu, 25 Nov 2004 16:19:02 +0900, Rob <spamrefuse@yahoo.com> wrote:
> >
> >
> >>>    time(minutes) * speed(MHz) * nproc / 1000 MHz
> >
> >
> >Looking at your examples, it seems you divide by 1e5, not by 1000.
>=20
> Sorry, yes you're right.
>=20
> >In other words, buildworld is CPU bound and takes about 6e12 clock
> >cycles.  Use -j<nproc>.
>=20
> 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):
>=20
>     time(minutes) =3D 1e5 / ( speed(MHz) * nproc )
>=20
> P-II    333 MHz : 300 min.
> P-III   700 MHz : 142 min.
> P-III 2x800 MHz :  62 min.
> P-IV   2000 MHz :  50 min.
>=20
> Within a few minutes, all these times are correct.
>=20
> I still have to test my P-I/150 MHz also running 5.3, and verify
> that buildworld will take approx. 670 min.

Of course, there are other factors that you don't consider that have a
huge impact on buildworld time, in particular disk performance.

Kris

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