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https://issues.apache.org/jira/browse/HDFS-8287?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14968720#comment-14968720
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Kai Sasaki commented on HDFS-8287:
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@Jing Zhao Thank you for reviewing! After submitting encoding task at #4, main
thread keeps to write next stripe into the current buffer.
So I think that the current patch utilizes the double buffer. If we move #2 to
the end, where the next stripe can be written?
The checksum calculation can be done with the encoding task.
{quote}
Besides, it will be nice to run some simple performance tests to see what
improvement the changes can achieve.
{quote}
I agree with you. I'll re-measure the performance with the current patch.
> DFSStripedOutputStream.writeChunk should not wait for writing parity
> ---------------------------------------------------------------------
>
> Key: HDFS-8287
> URL: https://issues.apache.org/jira/browse/HDFS-8287
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: hdfs-client
> Reporter: Tsz Wo Nicholas Sze
> Assignee: Kai Sasaki
> Attachments: HDFS-8287-HDFS-7285.00.patch,
> HDFS-8287-HDFS-7285.01.patch, HDFS-8287-HDFS-7285.02.patch,
> HDFS-8287-HDFS-7285.03.patch, HDFS-8287-HDFS-7285.04.patch,
> HDFS-8287-HDFS-7285.05.patch, HDFS-8287-HDFS-7285.06.patch,
> HDFS-8287-HDFS-7285.07.patch, HDFS-8287-HDFS-7285.08.patch,
> HDFS-8287-HDFS-7285.09.patch, HDFS-8287-HDFS-7285.10.patch,
> HDFS-8287-HDFS-7285.11.patch, HDFS-8287-HDFS-7285.WIP.patch,
> HDFS-8287-performance-report.pdf, HDFS-8287.12.patch, HDFS-8287.13.patch,
> HDFS-8287.14.patch, HDFS-8287.15.patch, h8287_20150911.patch, jstack-dump.txt
>
>
> When a stripping cell is full, writeChunk computes and generates parity
> packets. It sequentially calls waitAndQueuePacket so that user client cannot
> continue to write data until it finishes.
> We should allow user client to continue writing instead but not blocking it
> when writing parity.
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