> Integers, without the patch:
> 
>     dumps v3: 62.8 ms
>     data size v3: 4882.8 kB
>     loads v3: 10.7 ms
> 
> Integers, with the patch:
> 
>     dumps v3: 18.6 ms (-70%)
>     data size v3: 4882.8 kB (same size)
>     loads v3: 27.7 ms (+158%)

As I wrote on python-dev, dumps performance isn't important for the pyc
use case, but loads performance is. Therefore it appears this patch goes
into the wrong direction.

You are also ignoring the *runtime* benefit of sharing objects: smaller
memory footprint of the actual Python process.