[jira] [Commented] (MAPREDUCE-2841) Task level native optimization

["Sean Zhong (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MAPREDUCE-2841?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14040691#comment-14040691 ] 

Sean Zhong commented on MAPREDUCE-2841:
---------------------------------------

Latest native task code is posted at: https://github.com/intel-hadoop/nativetask/tree/native_output_collector for easy review. Currently the code is patched againt Hadoop2.2.

Some features highlights:
1. Full performance test covered https://github.com/intel-hadoop/nativetask/tree/native_output_collector#what-is-the-benefit
2. Support all values types which extends Writable.
3. Support all key types in hadoop.io, and most key types in project hive, pig, mahout, hbase. For a list of supported key types, please check https://github.com/intel-hadoop/nativetask/wiki#supported-key-types
4.  Fully support java combiner. 
5. Support large key and values.
6. A full test suite for key value combination.
7. Support GZIP, LZ4, and Snappy.

Items we are still working on:
1. Extract support  for  Hive/Pig/HBase/Mahout platforms to standalone jars, and decouple the dependency with native task source code.
2. More documents describing the api.

For design, test, and doc, please check
https://github.com/intel-hadoop/nativetask/tree/native_output_collector
https://github.com/intel-hadoop/nativetask/wiki



> Task level native optimization
> ------------------------------
>
>                 Key: MAPREDUCE-2841
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-2841
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>          Components: task
>         Environment: x86-64 Linux/Unix
>            Reporter: Binglin Chang
>            Assignee: Binglin Chang
>         Attachments: DESIGN.html, MAPREDUCE-2841.v1.patch, MAPREDUCE-2841.v2.patch, dualpivot-0.patch, dualpivotv20-0.patch, fb-shuffle.patch
>
>
> I'm recently working on native optimization for MapTask based on JNI. 
> The basic idea is that, add a NativeMapOutputCollector to handle k/v pairs emitted by mapper, therefore sort, spill, IFile serialization can all be done in native code, preliminary test(on Xeon E5410, jdk6u24) showed promising results:
> 1. Sort is about 3x-10x as fast as java(only binary string compare is supported)
> 2. IFile serialization speed is about 3x of java, about 500MB/s, if hardware CRC32C is used, things can get much faster(1G/
> 3. Merge code is not completed yet, so the test use enough io.sort.mb to prevent mid-spill
> This leads to a total speed up of 2x~3x for the whole MapTask, if IdentityMapper(mapper does nothing) is used
> There are limitations of course, currently only Text and BytesWritable is supported, and I have not think through many things right now, such as how to support map side combine. I had some discussion with somebody familiar with hive, it seems that these limitations won't be much problem for Hive to benefit from those optimizations, at least. Advices or discussions about improving compatibility are most welcome:) 
> Currently NativeMapOutputCollector has a static method called canEnable(), which checks if key/value type, comparator type, combiner are all compatible, then MapTask can choose to enable NativeMapOutputCollector.
> This is only a preliminary test, more work need to be done. I expect better final results, and I believe similar optimization can be adopt to reduce task and shuffle too. 



--
This message was sent by Atlassian JIRA
(v6.2#6252)