Date: Thu, 25 Nov 2004 18:52:51 -0800 From: Kris Kennaway <kris@obsecurity.org> To: Rob <spamrefuse@yahoo.com> Cc: freebsd-stable@freebsd.org Subject: Re: make -j$n buildworld : use of -j investigated Message-ID: <20041126025251.GA94802@xor.obsecurity.org> In-Reply-To: <41A698A5.6010601@yahoo.com> References: <opsh0jp9ge8527sy@smtp.local> <3282.1101377849@thrush.ravenbrook.com> <41A698A5.6010601@yahoo.com>
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--cNdxnHkX5QqsyA0e Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable 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 --cNdxnHkX5QqsyA0e Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (FreeBSD) iD8DBQFBppqDWry0BWjoQKURAikeAKCe+dH4+kWiao1zM2uCEjfHIK96kgCfT02v f+6bofoOLEtJY8xgxA8x25k= =O+96 -----END PGP SIGNATURE----- --cNdxnHkX5QqsyA0e--
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