Re: [Boost-build] Errors in windows with multiple parallel jobs

From: Jurko Gospodnetiæ (jurko.gospodnetic_at_[hidden])
Date: 2008-08-28 16:57:39

   Hi Felipe.

> On Thu, Aug 28, 2008 at 4:25 PM, Jurko Gospodnetiæ
> <jurko.gospodnetic_at_[hidden]> wrote:
>>  Hi Felipe.
>>
>>> I'm using a quad-core machine and using the last bjam from svn trunk
>>> (r48043).
>>> And as long as I use -j in bjam I have occasional problems where
>>> a install action tries to copy a file and fails, where the just before
>>> process creates that file. Also when trying to create lib files.
>>> I'm using windows vista x64.
>>> When I don't use -j it works fine.
>>  I believe this should be fixed now in the trunk. Could you please check
>> whether the latest trunk version of bjam works for you?
> 
> Yes, but it is rebuilding *a lot* of things that don't need to be rebuild.
> Anything I do, I end up building at least 188 targets (from a total
> of around 1200).

   Hmmm, could you construct an example demonstrating this, please?

   I do not see how exactly this change could introduce such 'extra 
target building' behaviour except in one special case and if that's what 
you have then it's a really really wierd build.

   It could happen if you have multiple A# targets (A1, A2, ... An) 
generated by a single action. Then if you have target X dependent only 
on Ax and that Ax is up-to-date but some other A# target target is not, 
Boost Build will think that X needs to be rebuilt even though it does 
not necessarily need to. It would need to be rebuilt only if something 
else forces any of the A# targets to be rebuilt as that would 
automatically rebuild the Ax target as well.

   Best regards,
     Jurko Gospodnetiæ