[Python-Dev] Accepting PEP 3154 for 3.4?

Nick Coghlan ncoghlan at gmail.com
Tue Nov 19 00:51:23 CET 2013

On 19 Nov 2013 09:33, "Tim Peters" <tim.peters at gmail.com> wrote:
> [Antoine]
> > Well, sending oceans of tiny integers will also incur many system calls
> > and additional synchronization costs, since sending data on a
> > multiprocessing Queue has to acquire a semaphore. So it generally
> > sounds like a bad idea, IMHO.
> >
> > That said, I agree with:
> >> Since pickle intends to be "the" Python serialization format, it
> >> really should try to be friendly for all plausible uses.
> >
> > I simply don't think adding a fixed 8-byte overhead is actually
> > annoying. It's less than the PyObject overhead in 64-bit mode...
> A long-running process can legitimately put billions of items on work
> queues, far more than could ever fit in RAM simultaneously.  Comparing
> this to PyObject overhead makes no sense to me.  Neither does the line
> of argument "there are several kinds of overheads, so making this
> overhead worse too doesn't matter".
> When possible, we should strive not to add overheads that don't repay
> their costs.  For small pickles, an 8-byte size field doesn't appear
> to buy anything.  But I appreciate that it costs implementation effort
> to avoid producing it in these cases.

Given that cases where the overhead matters can drop back to proto 3 if
absolutely necessary, perhaps it's reasonable to just run with the current


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