[Python-Dev] Experimenting with STM on CPython

[Charles-François Natali]

>> Yes, that's using STM on my regular laptop.  How HTM would help
>> remains unclear at this point, because in this approach transactions
>> are typically rather large --- likely much larger than what the
>> first-generation HTM-capable processors will support next year.
>
> Ok. I guess once the code is there, the hardware will eventually catch up.
>
> However, I'm not sure what you consider "large". A lot of manipulation
> operations for the builtin types are not all that involved, at least in the
> "normal" cases (read: fast paths) that involve no memory reallocation etc.,
> and anything that can be called by and doesn't call into the interpreter
> would be a complete and independent transaction all by itself, as the GIL
> is allowed to be released between any two ticks.

Large as in L2-cache large, and as in "you won't get a page fault or
an interrupt, you won't make any syscall, any I/O..." ;-)