GitHub user rogermenezes opened a pull request:
https://github.com/apache/spark/pull/6768
[SPARK-8314][MLlib] improvement in performance of MLUtils.appendBias
MLUtils.appendBias method is heavily used in creating intercepts for linear
models.
This method uses Breeze's vector concatenation which is very slow compared
to the plain
System.arrayCopy. This improvement is to change the implementation to use
System.arrayCopy.
I saw the following performance improvements after the change:
Benchmark with mnist dataset for 50 times:
MLUtils.appendBias (SparseVector Before): 47320 ms
MLUtils.appendBias (SparseVector After): 1935 ms
MLUtils.appendBias (DenseVector Before): 5340 ms
MLUtils.appendBias (DenseVector After): 4080 ms
This is almost a 24 times performance boost for SparseVectors.
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/rogermenezes/spark improve-append-bias
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/spark/pull/6768.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #6768
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commit e999d79ad76426614cc7a2db65a068ed402d0216
Author: Roger Menezes <[email protected]>
Date: 2015-06-11T22:37:37Z
first commit
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