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Posted to common-issues@hadoop.apache.org by "fanrui (Jira)" <ji...@apache.org> on 2020/08/24 17:29:00 UTC
[jira] [Updated] (HADOOP-17222) Create socket address combined with
cache to speed up hdfs client choose DataNode
[ https://issues.apache.org/jira/browse/HADOOP-17222?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
fanrui updated HADOOP-17222:
----------------------------
Attachment: Before optimization.svg
After optimization.svg
> Create socket address combined with cache to speed up hdfs client choose DataNode
> ---------------------------------------------------------------------------------
>
> Key: HADOOP-17222
> URL: https://issues.apache.org/jira/browse/HADOOP-17222
> Project: Hadoop Common
> Issue Type: Improvement
> Components: common, hdfs-client
> Environment: HBase version: 2.1.0
> JVM: -Xmx2g -Xms2g
> hadoop hdfs version: 2.7.4
> disk:SSD
> OS:CentOS Linux release 7.4.1708 (Core)
> JMH Benchmark: @Fork(value = 1)
> @Warmup(iterations = 300)
> @Measurement(iterations = 300)
> Reporter: fanrui
> Priority: Major
> Attachments: After Optimization remark.png, After optimization.svg, Before Optimization remark.png, Before optimization.svg
>
>
> Hdfs client selects best DN for hdfs Block. method call stack:
> DFSInputStream.chooseDataNode -> getBestNodeDNAddrPair -> NetUtils.createSocketAddr
> NetUtils.createSocketAddr creates the corresponding InetSocketAddress based on the host and port. There are some heavier operations in the NetUtils.createSocketAddr method, for example: URI.create(target), so NetUtils.createSocketAddr takes more time to execute.
> The following is my performance report. The report is based on HBase calling hdfs. HBase is a high-frequency access client for hdfs, because HBase read operations often access a small DataBlock (about 64k) instead of the entire HFile. In the case of high frequency access, the NetUtils.createSocketAddr method is time-consuming.
> h3. Test Environment：
>
> {code:java}
> HBase version: 2.1.0
> JVM: -Xmx2g -Xms2g
> hadoop hdfs version: 2.7.4
> disk:SSD
> OS:CentOS Linux release 7.4.1708 (Core)
> JMH Benchmark: @Fork(value = 1)
> @Warmup(iterations = 300)
> @Measurement(iterations = 300)
> {code}
> h4. Before Optimization FlameGraph:
> In the figure, we can see that DFSInputStream.getBestNodeDNAddrPair accounts for 4.86% of the entire CPU, and the creation of URIs accounts for a larger proportion.
> {{!Before Optimization remark.png|thumbnail!}}
> h3. Optimization ideas:
> NetUtils.createSocketAddr creates InetSocketAddress based on host and port. Here we can add Cache to InetSocketAddress. The key of Cache is host and port, and the value is InetSocketAddress.
> h4. After Optimization FlameGraph:
> In the figure, we can see that DFSInputStream.getBestNodeDNAddrPair accounts for 0.54% of the entire CPU. Here, ConcurrentHashMap is used as the Cache, and the ConcurrentHashMap.get() method gets data from the Cache. The CPU usage of DFSInputStream.getBestNodeDNAddrPair has been optimized from 4.86% to 0.54%.
> {{!After Optimization remark.png|thumbnail!}}
> h3. Original FlameGraph link:
> [Before Optimization|https://drive.google.com/file/d/133L5m75u2tu_KgKfGHZLEUzGR0XAfUl6/view?usp=sharing]
> [After Optimization FlameGraph|https://drive.google.com/file/d/133L5m75u2tu_KgKfGHZLEUzGR0XAfUl6/view?usp=sharing]
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