On Thu, Sep 7, 2017 at 2:40 PM, Benjamin Peterson <benjamin@python.org> wrote:
On Thu, Sep 7, 2017, at 14:19, Guido van Rossum wrote:
Nice one.
It would be nice to specify the various APIs needed as well.
The compileall and py_compile ones?
Yes, and the SipHash mod to specify the key you mentioned.
Why do you keep the mtime-based format as an option? (Maybe because it's faster? Did you measure it?)
I haven't actually measured anything, but stating a file will definitely be faster than reading it completely and hashing it. I suppose if the speed difference between timestamp-based and hash-based pycs turned out to be small we could feel good about dropping the timestamp format completely. However, that difference might be hard to determine definitely as I expect the speed hit will vary widely based on system parameters such as disk speed and page cache size.
My goal in this PEP was to preserve the current pyc invalidation behavior, which works well today for many use cases, as the default. The hash-based pycs are reserved for distribution and other power use cases.
OK, maybe you can clarify that a bit in the PEP. -- --Guido van Rossum (python.org/~guido)