Intel Core Duo. SMP kernel but still only 50% load while using make on ports...

[Bill Moran]

In response to Kris Kennaway <kris at obsecurity.org>:

> On Wed, Feb 07, 2007 at 04:44:42PM -0500, Bill Moran wrote:
> > In response to "Daniel Tourde" <daniel.tourde at spray.se>:
> > > 
> > >    Hello,
> > >    I have at my disposal an Inspiron 9400 with an Intel Core    FreeBSD 6.2
> > > is installed and rebuilt to fit the processor. The kerne   l is in SMP mode.
> > >    I noticed something strange: When I compile using ma   in the ports
> > > tree, I only have 50% load. CPU1 is used at   CPU0 is idle...
> > 
> > How do you know this?
> > 
> > >    I tried make -j2 but it did not work,   Any idea?
> > 
> > -j2 does not guarantee that you'll use both CPUs.  It's entirely possible
> > that the IO is slow enough that both of the processes are waiting on disk
> > and only able to push the overall system usage to 50%.  Try make -j99.
> 
> make -j in the ports tree is not going to compile the source in
> parallel, it is going to try and run the port targets in parallel (but
> they cannot be parallelized so nothing special will happen).  In
> theory it might work on some ports to pass in MAKE_ARGS=-j2, but a
> huge number of ports cannot be safely be compiled in parallel
> (i.e. the build will fail) because their developers have not added
> support for this.

Good point.  I was assuming that you were doing "make -j2 buildworld".

-- 
Bill Moran
Collaborative Fusion Inc.