D4502: util: allow lrucachedict to track cost of entries

[lothiraldan (Boris Feld)]

lothiraldan added inline comments.

INLINE COMMENTS

> indygreg wrote in util.py:1277
> Good catch! I'll send a revised patch.
> 
> FWIW, cost accounting on this data structure opens up a lot of potential around caching on revlogs. I have some alpha-quality commits to replace the full revision cache on the revlog with an `lrucachedict` and to add a decompressed chunk cache to revlogs. Such caches can speed up certain operations drastically. However, we need to be careful about adding always-on caches to revlogs because they can result in memory bloat. I was thinking about adding context manager methods to revlogs to temporarily activate certain aggressive caches in order to facilitate certain operations. e.g. a fulltext or chunk cache when applying delta groups could make it drastically faster to compute deltas during bulk insertion. A chunk cache could make reverse walks significantly faster. Etc. I figured you'd be interested given recent work in this area :)

Having a weighted cache would combine well with our work on intermediate snapshots. If we can keep the right intermediate snapshots in the cache we will get a lot of useful cache hit.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D4502

To: indygreg, #hg-reviewers
Cc: lothiraldan, mercurial-devel