[Scons-users] Batching behavior of the Parallel class in Jobs.py

[Dirk Bächle]

Hi Andrew,

On 05.10.2016 19:57, Andrew C. Morrow wrote:
>
> I noticed something a little odd, maybe, in the Parallel class:
>
> https://bitbucket.org/scons/scons/src/ea74a7f7a61561bebfbbfd5e7e70c4c346dd8bdb/src/engine/SCons/Job.py?at=default&fileviewer=file-view-default#Job.py-403:426
>
> The way I read this, Jobs are processed in 'batches', but this doesn't seem to be necessary. To experiment with this, I added prints
> at lines 396 and 407 to print the number of jobs. The current behavior when I do a -j12 build looks like:
>

thanks for noticing this. I haven't been around back then, but it appears to be an intended change from revision #1281 "Reap as many 
thread responses as possible at once.  (J.T. Conklin)". It's also reflected in one of the Taskmaster tests, so I'd expect that one 
to fail with your patch.
There's some more info about the background of this change in the threads

   http://osdir.com/ml/programming.tools.scons.user/2005-05/msg00025.html
   http://osdir.com/ml/programming.tools.scons.user/2005-05/msg00028.html
   http://osdir.com/ml/programming.tools.scons.devel/2005-05/msg00011.html

but I haven't digested these yet, such that I could say "I understand what they meant". It's definitely *not* an oversight...

Best regards,

Dirk