The RTDC
Processing SMA Data
1.2 m Telescopes
AST/RO
Extra

Running CASA: Timing Tests


A series of tests designed to find the optimal way to run CASA on the RTDC machines.

The tests run tclean on a mosaiced dataset (this includes the partition task for the parallel option). tclean is the CASA task that has the maximum gain from parallelization. Tests run using CASA 5.1.2.

Summary

  • Massive time gains by running tclean in parallel. Even using 3 cores is ~3x faster than serial processing.
  • Significant gains (~50%) from using machines with faster processors (actually a combination of CPU and disk performace).
  • No significant gain to using > 7 cores.
  • Better to use fewer, unshared cores, than more, shared cores.

Data sizeDisk typeMachineParallel?# CoresOther parametersTimeComments
6.4G NFS RTDC8 N - blockdev=64964h16m Data read from rglinux13
6.4G local RTDC8 N - blockdev=64963h50m Local disks definitely better
6.4G local RTDC8 Y 9 blockdev=6496 45m Repeated and it completed in 36m
6.4G local RTDC8 Y 7blockdev=6496 42m Repeated and it completed in 38m & 43m. Only a couple of minutes separate 7 and 9 cores.
6.4G local RTDC8 Y 7 blockdev=250 67m Confirms that blockdev makes a significant difference
6.4G local RTDC8 Y 5blockdev=6496 57m Fewer cores = longer. Repeated and it completed in 47m.
6.4G local RTDC8 Y 3blockdev=6496 85m Fewer cores = longer. As expected. Repeated and it completed in 73m.
6.4G local RTDC8N - blockdev=6496, mstransform[1, 256, 54] 3h3mSaving 20% on serial processing time using mstransform to trim
6.4G local RTDC8Y 7 blockdev=6496, mstransform[1, 256, 54] 39m No time gains
6.4G NFS RTDC8 Y 7 blockdev=649656m Data read from NFS mounted disk (rglinux13) & written locally.
6.4G NFS RTDC8 Y 7 blockdev=649678m All work done on NFS mounted disk (rtdc9 mounted on rtdc8)
6.4G NFS RTDC8 Y 7 blockdev=649694mAll work done on NFS mounted disk (rglinux13 mounted on rtdc8)
6.4G NFS RTDC8 Y 7 blockdev=649658m All work done on local RTDC8 disk that is mounted as NFS at mount point.
6.4G NFS RTDC8 Y 7 blockdev=649656m Local disks on rtdc8 mounted as NFS
6.4G local RGLINUX13 Y 7 blockdev=6496, CPU speed 2.9GHz78m
13G local RTDC8Y 5 blockdev=6496 57m Compare to 57 mins for half the data
13G local RTDC8Y 9 blockdev=6496 54m Compare to 42 mins for half the data
13G local RTDC8Y 13 blockdev=6496 48m
13G local RTDC8Y 15x2 blockdev=6496 101m & 102m Set two identical scripts running simultaneously.

Better to run with fewer unshared cores, than to run with more cores that are shared.

13G local RTDC8Y 7x2 blockdev=6496 79m & 77mm
6.4G local RTDC8 Y 5blockdev=6496 110m Re-run with CASA 5.3.0

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