PPC kernel build times

[Josh Boyer]

So I poked around at why ppc builds seem so slow.  Net result:
I still have no idea.

On a quad-970 machine with 2GiB of DRAM running the latest F-9,
I did a 'make ppc64' build of the devel kernel with a modified
kernel.spec file that spit out some basic timestamps on the
RPM sections.  Results:

Total time:

real	65m58.701s
user	89m53.501s
sys	11m4.737s

Each section:

Prep:     52 seconds
Build:   ~33 minutes
Install:  38 seconds

[jwboyer at yoda devel]$ grep -e Prep -e Build -e Install .build-2.6.29-0.39.rc1.git5.fc11.log | grep -v +
Building target platforms: ppc64
Building for target ppc64
Prep Start: Thu Jan 15 15:48:16 EST 2009
Prep End: Thu Jan 15 15:49:08 EST 2009
Build Start: Thu Jan 15 15:49:08 EST 2009
Build End: Thu Jan 15 16:22:57 EST 2009
Install Start: Thu Jan 15 16:22:57 EST 2009
Install End: Thu Jan 15 16:23:35 EST 2009


The overall time is slightly faster than the koji builds I've seen by
a few minutes.  This is somewhat expected, as my box wasn't really
doing much else at the time and some of the builders are blades with
fewer cores and slower hard drives.

Since I had nothing better to do in my sad life, I was watching the top
output a bit during one of my builds.  I noticed that when rpmbuild
got to the part where it was writing out the -debuginfo RPM, it took
almost 18 minutes.  Why this is, I have no idea.

For gits and shiggles, I grabbed the config from the resulting RPM and
used it with a 'time make -j4' on Linus' latest git tree:

real	28m46.829s
user	70m30.520s
sys	7m43.533s

So the build time seems roughly equivalent.  Yay for doing stuff that
garners no new insight!

josh