[infinispan-dev] Eviction maxEntries analysis

[Martin Gencur]

Hi all,
I ran a few tests to find out what is the actual number of entries held
in a cache when certain "maxEntries" param is set for eviction and I
store more than maxEntries entries. I tested with HotSpot JDK6 [1], IBM
JDK 6,7 [2]. OpenJDK6 seems to have the same results as HotSpot JDK. 

Results:

maxEntries being set -> actual number of entries held in the cache

HotSpot JDK:
------------

2 -> 2
4 -> 4
6 -> 4
8 -> 8
10 -> 8
256 -> 232
300 -> 266

IBM JDK (both 6, 7):
--------------------

2 -> 4 (2 with LIRS)
4 -> 6 (4 with LIRS)
6 -> 10 
8 -> 11 (8 with LIRS)
10 -> 13, (8 with LIRS)
300 -> 287, (266 with LIRS)
256 -> 247, (232 with LIRS)

I modified one test in ispn-core to do this testing:
https://github.com/mgencur/infinispan/commit/837a1c752fa7fbfb3f05738dd873e78cbf71d071



Any thoughts ? :)



[1] 

java version "1.6.0_21"
Java(TM) SE Runtime Environment (build 1.6.0_21-b06)
Java HotSpot(TM) 64-Bit Server VM (build 17.0-b16, mixed mode)

[2]

java version "1.6.0"
Java(TM) SE Runtime Environment (build pxi3260sr9fp1-20110208_03(SR9
FP1))
IBM J9 VM (build 2.4, JRE 1.6.0 IBM J9 2.4 Linux x86-32
jvmxi3260sr9-20110203_74623 (JIT enabled, AOT enabled)

java version "1.7.0"
Java(TM) SE Runtime Environment (build pxi3270-20110827_01)
IBM J9 VM (build 2.6, JRE 1.7.0 Linux x86-32 20110810_88604 (JIT
enabled, AOT enabled)



-- 
Martin Gencur
--
JBoss QE, Enterprise Data Grid
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