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https://issues.apache.org/jira/browse/HBASE-22412?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16843685#comment-16843685
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Zheng Hu commented on HBASE-22412:
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bq. you want to show the actual allocation on heap to be much lesser than the
number of allocations ?
The allocationNum can not show the heapAllocationRatio correctly now. because
if we want to allocate 65KB, then the 64KB will be allocated from pool and the
remaining 1KB will be allocated from heap. Then the ratio will always be 50%,
that's not right.
Thanks for the reviewing, I will do the commit.
> Improve the metrics in ByteBuffAllocator
> ----------------------------------------
>
> Key: HBASE-22412
> URL: https://issues.apache.org/jira/browse/HBASE-22412
> Project: HBase
> Issue Type: Sub-task
> Reporter: Zheng Hu
> Assignee: Zheng Hu
> Priority: Major
> Attachments: HBASE-22412.HBASE-21879.v1.patch,
> HBASE-22412.HBASE-21879.v2.patch, HBASE-22412.HBASE-21879.v3.patch, JMX.png,
> web-UI.png
>
>
> gAddress the comment in HBASE-22387:
> bq. The ByteBuffAllocator#getFreeBufferCount will be O(N) complexity, because
> the buffers here is an ConcurrentLinkedQueue. It's worth file an issue for
> this.
> Also I think we should use the allcated bytes instead of allocation number to
> evaluate the heap allocation percent , so that we can decide whether the
> ByteBuffer is too small and whether will have higher GC pressure. Assume the
> case: the buffer size is 64KB, and each time we have a block with 65KB, then
> it will have one heap allocation (1KB) and one pool allocation (64KB), if
> only consider the allocation num, then the heap allocation ratio will be 1 /
> (1 + 1) = 50%, but if consider the allocation bytes, the allocation ratio
> will be 1KB / 65KB = 1.5%.
> If the heap allocation percent is less than
> hbase.ipc.server.reservoir.minimal.allocating.size /
> hbase.ipc.server.allocator.buffer.size, then the allocator works fine,
> otherwise it's overload.
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