[Python-Dev] refleaks and caches (original) (raw)

Neal Norwitz nnorwitz at gmail.com
Mon Jan 28 01:35:35 CET 2008

On Jan 27, 2008 3:37 PM, Christian Heimes <lists at cheimes.de> wrote:

Phillip J. Eby wrote: > Expose an API to clear the cache, and clear it at shutdown? It > should probably be part of interpreter shutdown anyway.

Good point. I've implemented PyTypeClearCache and exposed it via sys.cleartypecache(). The function is called during finalization, too.

I'm not sure we should expose an API to clear the cache, but I don't have strong opinions either way. If we keep the ability to clear the cache, should we also consider some control over the int/float freelist? These are worse than the tuple/frame free lists since int/floats are unbounded. I suspect the method free lists in Objects/methodobject.c and Objects/classobject.c don't have that many entries that could be removed.

There may not be a lot we can do for the int/float caches and I'm not sure if it's worth it. We can't move objects once created, although we could scan the blocks and if there are no live objects in a block, free it. That would presumably help with this case:

list(range(some_big_number))

I don't know how important these things are in practice.

Can somebody please double check the change? The results are promising and I'm sure I've implemented it correctly but you never know ;)

The biggest problem I have with the patch is the attribute name. I would prefer underscores. ie _clear_type_cache instead of _cleartypecache. Attributes in sys are currently inconsistent, but it seems that most of the newer names have underscores. (Aside: if we are going to move attrs out of sys for py3k, we should consider renaming them to be consistent too. Regardless of moving them, should we rename them.)

n

More information about the Python-Dev mailing list