depend + all vs dependall

[Bruce Evans]

On Mon, 31 Mar 2003, Ruslan Ermilov wrote:

> On Mon, Mar 31, 2003 at 09:06:07PM +1000, Bruce Evans wrote:
> > On Mon, 31 Mar 2003, Ruslan Ermilov wrote:
> > > On a Celeron 800 system with ATA100 disk using -j4 -DNOCLEAN buildworld
> > > of RELENG_4 a friend reported the following times:
> > >
> > > Without patch		With patch
> > > real    69m43.271s	69m26.722s
> > > user    38m22.009s	38m19.384s
> > > sys     10m45.273s	10m41.596s
> > >
> > > Further reports show that on single-CPU systems with large CPU
> > > cache the real time win was near what I have reported for 2-CPU
> > > box, and it had no effect on small cache single-CPU systems and
> > > -j builds.
> >
> > I think I understand why it often makes little difference: it saves
> > a tree traversal, but costs an extra make process for each leaf
> > directory.
> >
> Hardly so.  My patch doesn't affect leaf directories; only
> level 1 bsd.subdir.mk makefiles (*bin*/Makefile, etc.) are
> affected by this parallelization.

I thought that the above times were for dependall and was trying to
explain why the optimization was so small.

Bruce