Details
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Type:
Story
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Status: Done
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Resolution: Done
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Fix Version/s: None
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Component/s: afw
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Labels:None
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Story Points:5
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Epic Link:
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Sprint:Science Pipelines DM-S15-3
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Team:Data Release Production
Description
In DM-1128 we implemented span-based dilation for footprints. A brief test on synthetic data indicated that this was a performance win over the previous version of the code.
In May 2015, this code was merged to HSC and applied to significant quantities of real data for the first time. A major performance regression was identified:
[May-9 00:26] Paul Price: processCcd is now crazy slow.
[May-9 00:29] Paul Price: Profiling...
[May-9 00:40] Paul Price: I'm thinking it's the Footprint grow code...
[May-9 00:44] Paul Price: And the winner is…. Footprint construction:
[May-9 00:44] Paul Price: 2 0.000 0.000 702.280 351.140 /home/astro/hsc/products/Linux64/meas_algorithms/HSC-3.8.0/python/lsst/meas/algorithms/detection.py:191(makeSourceCatalog) 2 0.005 0.002 702.274 351.137 /home/astro/hsc/products/Linux64/meas_algorithms/HSC-3.8.0/python/lsst/meas/algorithms/detection.py:228(detectFootprints) 15 0.001 0.000 698.597 46.573 /home/pprice/hsc/afw/python/lsst/afw/detection/detectionLib.py:3448(_init_) 15 698.596 46.573 698.596 46.573 {_detectionLib.new_FootprintSet}
[May-9 00:53] Paul Price: If I revert HSC-1243 ("Port better Footprint-grow code from LSST"), then the performance regression goes away. @jbosch @jds may be interested...
The source of the regression must be identified and resolved for both HSC and LSST.
Glad we got to the bottom of this! Sorry it took longer than we would have liked...