Bhaskar Devireddy created MAHOUT-1035:
-----------------------------------------
Summary: Hotspot in recommenditembased – UnsymmetrifyMapper job
Key: MAHOUT-1035
URL: https://issues.apache.org/jira/browse/MAHOUT-1035
Project: Mahout
Issue Type: Improvement
Components: Collaborative Filtering
Affects Versions: 0.7
Reporter: Bhaskar Devireddy
Assignee: Sean Owen
Priority: Minor
Fix For: 0.8
While profiling the unsymmetrify mapper job in recommendations we noticed an
hotspot consuming 90% of the CPU runtime in
org.apache.mahout.math.map.OpenIntDoubleHashMap.keys method for the first map
task. We used the script provided in mahout examples for running ASF Email
recommendations for profiling. The attached patch addresses the hotspot by
reducing the number of for loop iterations in OpenIntDoubleHashMap.keys method
by changing the initialization of transposedPartial. This patch while
retaining functionality(verified the output with and without patch) speeds up
the unsymmetrify mapper task by more than 4X on x86 architectures.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
