[yocto] Build time data

[Chris Tapp]

On 18 Apr 2012, at 21:55, Darren Hart wrote:

<snip>

> A couple of things to keep in mind here. The minimal build is very
> serialized in comparison to something like a sato build. If you want to
> optimize your build times, look at the bbmatrix* scripts shipped with
> poky to find the sweet spot for your target image and your build system.
> I suspect you will find your BB_NUMBER_THREADS and PARALLEL_MAKE
> settings are two high for your system. I'd start with them at 8 and 8,
> or 8 and 6 respectively.

I've run a few of the matrix variants (it's going to take a few days to get a full set). 8 and 16 threads are giving the same results (within a few seconds) for parallel make values in the range 6 to 12.

I tried a core-image-sato build and it completed in 61m/244m/40m, which is much closer to your <50m than I thought I would get.

One thing I noticed during the build was that gettext-native seemed slow. Doing a 'clean' on it and re-baking shows that it takes over 4 minutes to build with most of the time (2m38) being spent in 'do_configure'. It also seems as if this is on the critical path as nothing else was getting scheduled while it was building. There seems to be a lot of 'nothing' going on during the do_configure phase (i.e. very little CPU use). Or, to put it another way, 2.5% of the build time is taken up configuring this package!

> IPK is faster than RPM. This is what I use on most of my builds.

Makes no noticeable difference in my testing so far, but I'll stick with IPK from now on.

<snip>

> Run the ubuntu server kernel to eliminate some scheduling overhead.
> Reducing the parallel settings mentioned above should help here too.

I'm running 11.x server as you mentioned this before ;-)

Chris Tapp

opensource at keylevel.com
www.keylevel.com