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https://issues.apache.org/jira/browse/HBASE-14613?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14959810#comment-14959810
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stack commented on HBASE-14613:
-------------------------------
Nice link [~enis]
Looks like 8M in CMS ... or somewhere between 4M and 8M. And 1M for G1.
{code}
[stack@c2020 tenured-allocation]$ ~/bin/jdk1.7.0_67/bin/java
-XX:+PrintCommandLineFlags -Xmn16m -Xmx1g -jar
target/tenured-allocation-1.0-SNAPSHOT.jar
-XX:InitialHeapSize=790664512 -XX:MaxHeapSize=1073741824
-XX:MaxNewSize=16777216 -XX:NewSize=16777216 -XX:+PrintCommandLineFlags
-XX:+UseCompressedOops -XX:+UseParallelGC
Tracking memory usage with PS Eden Space and PS Old Gen
Allocation in Eden: 65536 (capacity: 12582912)
Allocation in Eden: 131072 (capacity: 12582912)
Allocation in Eden: 262144 (capacity: 12582912)
Allocation in Eden: 524288 (capacity: 12582912)
Allocation in Eden: 1048576 (capacity: 12582912)
Allocation in Eden: 2097152 (capacity: 12582912)
Allocation in Eden: 4194304 (capacity: 12582912)
Direct allocation in Tenured: 8388608 (Eden capacity: 12582912)
Direct allocation in Tenured: 16777216 (Eden capacity: 12582912)
Allocation size (16777216) greater than Eden capacity (12582912)
[stack@c2020 tenured-allocation]$
[stack@c2020 tenured-allocation]$ ~/bin/jdk1.7.0_67/bin/java -XX:+UseG1GC
-XX:+PrintCommandLineFlags -Xmn16m -Xmx1g -jar
target/tenured-allocation-1.0-SNAPSHOT.jar
-XX:InitialHeapSize=790664512 -XX:MaxHeapSize=1073741824
-XX:MaxNewSize=16777216 -XX:NewSize=16777216 -XX:+PrintCommandLineFlags
-XX:+UseCompressedOops -XX:+UseG1GC
Tracking memory usage with G1 Eden Space and G1 Old Gen
Allocation in Eden: 65536 (capacity: 17825792)
Allocation in Eden: 131072 (capacity: 17825792)
Allocation in Eden: 262144 (capacity: 17825792)
Allocation in Eden: 524288 (capacity: 17825792)
Direct allocation in Tenured: 1048576 (Eden capacity: 17825792)
Direct allocation in Tenured: 2097152 (Eden capacity: 17825792)
Direct allocation in Tenured: 4194304 (Eden capacity: 17825792)
Direct allocation in Tenured: 8388608 (Eden capacity: 17825792)
Direct allocation in Tenured: 16777216 (Eden capacity: 17825792)
Direct allocation in Tenured: 33554432 (Eden capacity: 17825792)
Allocation size (33554432) greater than Eden capacity (17825792)
[stack@c2020 tenured-allocation]$ ~/bin/jdk1.8.0_60/bin/java
-XX:+PrintCommandLineFlags -Xmn16m -Xmx1g -jar
target/tenured-allocation-1.0-SNAPSHOT.jar
-XX:InitialHeapSize=790664512 -XX:MaxHeapSize=1073741824
-XX:MaxNewSize=16777216 -XX:NewSize=16777216 -XX:+PrintCommandLineFlags
-XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseParallelGC
Tracking memory usage with PS Eden Space and PS Old Gen
Allocation in Eden: 65536 (capacity: 12582912)
Allocation in Eden: 131072 (capacity: 12582912)
Allocation in Eden: 262144 (capacity: 12582912)
Allocation in Eden: 524288 (capacity: 12582912)
Allocation in Eden: 1048576 (capacity: 12582912)
Allocation in Eden: 2097152 (capacity: 12582912)
Allocation in Eden: 4194304 (capacity: 12582912)
Direct allocation in Tenured: 8388608 (Eden capacity: 12582912)
Direct allocation in Tenured: 16777216 (Eden capacity: 12582912)
Allocation size (16777216) greater than Eden capacity (12582912)
[stack@c2020 tenured-allocation]$ ~/bin/jdk1.8.0_60/bin/java -XX:+UseG1GC
-XX:+PrintCommandLineFlags -Xmn16m -Xmx1g -jar
target/tenured-allocation-1.0-SNAPSHOT.jar
-XX:InitialHeapSize=790664512 -XX:MaxHeapSize=1073741824
-XX:MaxNewSize=16777216 -XX:NewSize=16777216 -XX:+PrintCommandLineFlags
-XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseG1GC
Tracking memory usage with G1 Eden Space and G1 Old Gen
Allocation in Eden: 65536 (capacity: 17825792)
Allocation in Eden: 131072 (capacity: 17825792)
Allocation in Eden: 262144 (capacity: 17825792)
Allocation in Eden: 524288 (capacity: 17825792)
Direct allocation in Tenured: 1048576 (Eden capacity: 17825792)
Direct allocation in Tenured: 2097152 (Eden capacity: 17825792)
Direct allocation in Tenured: 4194304 (Eden capacity: 17825792)
Direct allocation in Tenured: 8388608 (Eden capacity: 17825792)
Direct allocation in Tenured: 16777216 (Eden capacity: 17825792)
Direct allocation in Tenured: 33554432 (Eden capacity: 17825792)
Allocation size (33554432) greater than Eden capacity (17825792)
{code}
> Remove MemStoreChunkPool?
> -------------------------
>
> Key: HBASE-14613
> URL: https://issues.apache.org/jira/browse/HBASE-14613
> Project: HBase
> Issue Type: Brainstorming
> Reporter: Lars Hofhansl
> Priority: Minor
> Attachments: 14613-0.98.txt
>
>
> I just stumbled across MemStoreChunkPool. The idea behind is to reuse chunks
> of allocations rather than letting the GC handle this.
> Now, it's off by default, and it seems to me to be of dubious value. I'd
> recommend just removing it.
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