[jira] [Commented] (HDFS-10690) Optimize insertion/removal of replica in ShortCircuitCache

2016-10-05 Thread Fenghua Hu (JIRA) 

[ 
https://issues.apache.org/jira/browse/HDFS-10690?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15550451#comment-15550451
 ] 

Fenghua Hu commented on HDFS-10690:
---

[~xyao], thank you for the great help!

> Optimize insertion/removal of replica in ShortCircuitCache
> --
>
> Key: HDFS-10690
> URL: https://issues.apache.org/jira/browse/HDFS-10690
> Project: Hadoop HDFS
>  Issue Type: Improvement
>  Components: hdfs-client
>Affects Versions: 3.0.0-alpha2
>Reporter: Fenghua Hu
>Assignee: Fenghua Hu
> Fix For: 2.8.0
>
> Attachments: HDFS-10690.001.patch, HDFS-10690.002.patch, 
> HDFS-10690.003.patch, HDFS-10690.004.patch, HDFS-10690.005.patch, 
> HDFS-10690.006.patch, HDFS-10690.007.patch, HDFS-10690.008.patch, 
> ShortCircuitCache_LinkedMap.patch
>
>   Original Estimate: 336h
>  Remaining Estimate: 336h
>
> Currently in ShortCircuitCache, two TreeMap objects are used to track the 
> cached replicas.
> private final TreeMap evictable = new TreeMap<>();
> private final TreeMap evictableMmapped = new 
> TreeMap<>();
> TreeMap employs Red-Black tree for sorting. This isn't an issue when using 
> traditional HDD. But when using high-performance SSD/PCIe Flash, the cost 
> inserting/removing an entry  becomes considerable.
> To mitigate it, we designed a new list-based for replica tracking.
> The list is a double-linked FIFO. FIFO is time-based, thus insertion is a 
> very low cost operation. On the other hand, list is not lookup-friendly. To 
> address this issue, we introduce two references into ShortCircuitReplica 
> object.
> ShortCircuitReplica next = null;
> ShortCircuitReplica prev = null;
> In this way, lookup is not needed when removing a replica from the list. We 
> only need to modify its predecessor's and successor's references in the lists.
> Our tests showed up to 15-50% performance improvement when using PCIe flash 
> as storage media.
> The original patch is against 2.6.4, now I am porting to Hadoop trunk, and 
> patch will be posted soon.



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[jira] [Commented] (HDFS-10690) Optimize insertion/removal of replica in ShortCircuitCache

2016-10-03 Thread Hudson (JIRA) 

[ 
https://issues.apache.org/jira/browse/HDFS-10690?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel=15543081#comment-15543081
 ] 

Hudson commented on HDFS-10690:
---

SUCCESS: Integrated in Jenkins build Hadoop-trunk-Commit #10533 (See 
[https://builds.apache.org/job/Hadoop-trunk-Commit/10533/])
HDFS-10690. Optimize insertion/removal of replica in ShortCircuitCache. (xyao: 
rev 607705c488fa5263d851cee578a2d319e6e52ecd)
* (edit) 
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/shortcircuit/TestShortCircuitCache.java
* (edit) 
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/fs/TestEnhancedByteBufferAccess.java
* (edit) 
hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/shortcircuit/ShortCircuitCache.java


> Optimize insertion/removal of replica in ShortCircuitCache
> --
>
> Key: HDFS-10690
> URL: https://issues.apache.org/jira/browse/HDFS-10690
> Project: Hadoop HDFS
>  Issue Type: Improvement
>  Components: hdfs-client
>Affects Versions: 3.0.0-alpha2
>Reporter: Fenghua Hu
>Assignee: Fenghua Hu
> Fix For: 2.8.0
>
> Attachments: HDFS-10690.001.patch, HDFS-10690.002.patch, 
> HDFS-10690.003.patch, HDFS-10690.004.patch, HDFS-10690.005.patch, 
> HDFS-10690.006.patch, HDFS-10690.007.patch, HDFS-10690.008.patch, 
> ShortCircuitCache_LinkedMap.patch
>
>   Original Estimate: 336h
>  Remaining Estimate: 336h
>
> Currently in ShortCircuitCache, two TreeMap objects are used to track the 
> cached replicas.
> private final TreeMap evictable = new TreeMap<>();
> private final TreeMap evictableMmapped = new 
> TreeMap<>();
> TreeMap employs Red-Black tree for sorting. This isn't an issue when using 
> traditional HDD. But when using high-performance SSD/PCIe Flash, the cost 
> inserting/removing an entry  becomes considerable.
> To mitigate it, we designed a new list-based for replica tracking.
> The list is a double-linked FIFO. FIFO is time-based, thus insertion is a 
> very low cost operation. On the other hand, list is not lookup-friendly. To 
> address this issue, we introduce two references into ShortCircuitReplica 
> object.
> ShortCircuitReplica next = null;
> ShortCircuitReplica prev = null;
> In this way, lookup is not needed when removing a replica from the list. We 
> only need to modify its predecessor's and successor's references in the lists.
> Our tests showed up to 15-50% performance improvement when using PCIe flash 
> as storage media.
> The original patch is against 2.6.4, now I am porting to Hadoop trunk, and 
> patch will be posted soon.



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