[yocto] Why did my build need to redo so many tasks?

[Barros Pena, Belen]

On 12/02/2015 22:19, "Martin Jansa" <martin.jansa at gmail.com> wrote:

>On Thu, Feb 12, 2015 at 02:25:32PM -0700, Gary Thomas wrote:
>> Yesterday, I built a large image using Poky/Yocto 870323cac1e
>> Today I updated my Poky repo to 231d4a9d3
>> 
>> When I rebuilt the same image, bitbake kicked off more than
>> 5200 tasks, building virtually every package from scratch.
>> 
>> How can I tell why this happened?  I don't have buildhistory
>> enabled, but I do still have the tmp & sstate-cache trees
>> from the process.  Is there enough info laying around that
>> I can tell, e.g. why the GCC toolchain had to be rebuilt
>> completely?
>> 
>> Am I correct in assuming that bitbake-whatchanged is really
>> a Quija board and can only tell me [in advance] what will need
>> to be done if my layers change?  When I ran it after the long
>> build above, it didn't really tell me much :-(
>
>I'm using
>openembedded-core/scripts/sstate-diff-machines.sh
>to create sstate signature snaphosts for interesting builds, then
>when I'm surprised by number of re-executions, I create another snapshot
>and compare them.

And there is Toaster, which also reports on sstate use, although after the
build is done and it might not give you the same granularity as the other
suggestions. It looks nice, though ;)

Belén

>
>-- 
>Martin 'JaMa' Jansa     jabber: Martin.Jansa at gmail.com