[distcc] Using distcc on two ARM boards resulted in almost no acceleration...

[James W Mills]

Hello list!

First of all, thanks for this great tool.  If I can get it to work for me, it will really help!

Okay, I have two OMAP4430 Panda boards, both running a 2.6.34 kernel and Ubuntu 10.10 Maverick.  They are running distcc version 3.1, and gcc version 4.4.4, both native ports by Ubuntu for the arm.

These two machines are connected to each other via ethernet on a private switched network.  They have an ~50Mb/s link.  I have configured distccd on the host machine (192.168.1.20) to listen to all interfaces (0.0.0.0), and to allow connections from "127.0.0.1 192.168.1.0/24".  The remote machine (192.168.1.10) is configured to allow "127.0.0.1 192.168.1.0/24" and to listen on 192.168.1.10.

I am building a 2.6.34 kernel (make uImage).  I have built 4 times, twice locally, and twice "distributed".  Here are my results:

make clean
time make CC="distcc gcc" DISTCC_HOSTS="localhost 192.168.1.10" -j8 uImage
real    44m44.648s
user    30m4.039s
sys     4m0.313s

make clean
time make CC="distcc gcc" DISTCC_HOSTS="localhost 192.168.1.10" -j4 uImage
real    42m32.055s
user    33m46.500s
sys     3m55.273s

make clean
time make -j4 uImage
real    45m19.444s
user    57m2.945s
sys     3m54.578s

make clean
time make -j2 uImage
real    45m10.431s
user    54m29.516s
sys     3m56.813s


As you can see, I saw no "real" speedup by using distcc.  Is there something I am doing wrong?

I'd appreciate any help, and please let me know if you need more in-depth information from me.

Thanks!
James