Missing LU and LRU is linear complexity - performance


  • Type: Defect Defect
  • Status: Open Open
  • Priority: Major Major
  • Resolution: Unresolved
  • Affects Version/s: None
  • Fix Version/s: None
  • Component/s: None
  • Environment:
    Mac Oracle JDK, Linux OpenJDK
  • Patch:


Profiling some code with YourKit showed a hotspot in cache statistics on (miss) for LU and LRU caches.

Basically two issues: (count (keys {....})) is a count of a seq, not efficient. Replaced with a count of the map.

Secondly, (apply f anything) is slow. Profiler showed that the (apply min-key) was really slow. This is mitigated by using a c.d.priority-map instead. On a priority-map, (ffirst {}) or (first (peek {}).

Also inverted the logic for threshold comparison. Since there is a (build-leastness-queue) that populates statistics, should caches should favor codepaths for the state of being full all the time?

  1. priority-map.patch
    04/Sep/12 11:26 AM
    5 kB
    Ghadi Shayban
  2. priority-map-fixed.patch
    12/Sep/12 9:27 AM
    6 kB
    Ghadi Shayban


Ghadi Shayban made changes -
Field Original Value New Value
Attachment priority-map-fixed.patch [ 11492 ]


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