[ https://issues.apache.org/jira/browse/SYSTEMML-1753?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Matthias Boehm closed SYSTEMML-1753. ------------------------------------ > OOM on parfor local in-memory result merge > ------------------------------------------ > > Key: SYSTEMML-1753 > URL: https://issues.apache.org/jira/browse/SYSTEMML-1753 > Project: SystemML > Issue Type: Bug > Reporter: Matthias Boehm > Assignee: Matthias Boehm > Fix For: SystemML 1.0 > > > Consider a scenario with relatively large parfor result variable (e.g., many > iterations with relatively large output vector each). There are conditions > under which the parfor local in-memory result merge runs unnecessarily out of > memory (as shown below) due to allocating the result in sparse, collecting > all (sparse) outputs and finally converting this result to dense. For result > merge without compare, the target number of non-zeros are exactly known, > allowing us to directly allocate the result in the correct format, which > reduces memory pressure by more than 2x (dense matrix in sparse format). > {code} > Exception in thread "main" java.lang.OutOfMemoryError: Java heap space > at > org.apache.sysml.runtime.matrix.data.MatrixBlock.allocateDenseBlock(MatrixBlock.java:362) > at > org.apache.sysml.runtime.matrix.data.MatrixBlock.sparseToDense(MatrixBlock.java:1136) > at > org.apache.sysml.runtime.matrix.data.MatrixBlock.examSparsity(MatrixBlock.java:1019) > at > org.apache.sysml.runtime.controlprogram.parfor.ResultMergeLocalMemory.executeSerialMerge(ResultMergeLocalMemory.java:114) > at > org.apache.sysml.runtime.controlprogram.ParForProgramBlock.consolidateAndCheckResults(ParForProgramBlock.java:1751) > at > org.apache.sysml.runtime.controlprogram.ParForProgramBlock.executeLocalParFor(ParForProgramBlock.java:814) > at > org.apache.sysml.runtime.controlprogram.ParForProgramBlock.execute(ParForProgramBlock.java:635) > at > org.apache.sysml.runtime.controlprogram.Program.execute(Program.java:123) > {code} -- This message was sent by Atlassian JIRA (v6.4.14#64029)