[PyKDE] [PATCH] reduce PyQt concatenated build time on SMP

[Phil Thompson]

On Monday 24 March 2003 2:50 pm, Gerard Vermeulen wrote:
> On Mon, Mar 24, 2003 at 03:09:17PM +0100, Hans-Peter Jansen wrote:
> > On Monday 24 March 2003 13:05, Phil Thompson wrote:
> > > On Monday 24 March 2003 11:53 am, Hans-Peter Jansen wrote:
> > > > Hi Phil,
> > > >
> > > > in order to saturate multiple CPUs on SMP systems, I've created the
> > > > attached patch.
> > > >
> > > > The problem is, that the qt module consists of 228 single modules,
> > > > and build of its concatenated module outlasts all others by a few
> > > > minutes here.
> > > >
> > > > With it applied, I was able to reduce the rpm build time from 16:15
> > > > to 13.30 on my Dual P3/1000.
> > > >
> > > > Since it is created on top of my former patch, it will apply with
> > > > offsets, if applied first.
> > >
> > > But doesn't this slow it down for everybody with a UP machine?
> > >
> > > Phil
> >
> > Well, yes, I have to admit. But the performance hit is less then the
> > improvement, aka 19:53 -> 21:29 UP, AMD 2000+ (~8%), 16:15 -> 13:30
> > (~20%).
> >
> > Would you accept a combined cleaned up patch with different lower case
> > options for this and the lib stuff?
>
> If you are proposing this, why don't you generalize and code something like
> the -j switch (parallel build switch) for make.
>
> In this case there is no penalty for UP machines (by default one single
> huge.cpp), and the guys with 4 processors will feel happy, too :-)

Yes - I'd be happy with this. It also helps those compilers (aka MSVC) that 
choke on such a large C++ file but would probably handle...

python build.py -c -j 10

Phil