[TangerineSDR] Benchmarking Digital RF (HDF5)

[Engelke, Bill]

Benchmarking Digital_rf on Odroid

There have been some deep concerns about the ability of a SBC to keep up with saving spectrum data using HDF5 (here using the MIT Digital_rf package, which uses HDF5 internally). I installed Digital_rf on my Odroid XU4 and ran the benchmarks that are included in the Examples folder.

Writing to MicroSd card in the XU4 (SanDisk Ultra Plus, claimed speed 80 MB/sec), benchmark-reported speeds
1.                     Writing raw binary data directly                                           133.36  MB/sec
2.                     Writing "simple single write" in HDF5                                 154.14 MB/sec
3.                     Writing "simple single write" in HDF5 with checksum        71.29 MB/sec
4.                     Writing      "        "    "  with checksum + compression L1        8.01 MB/sec
Unexpected results here:
a. HDF5 "simple write" is faster than writing raw binary
b. top two speeds are faster than the claimed speed of the MicroSD card. Maybe the benchmark is measuring a burst rate during just the HDF5 processing (?) Maybe there is some caching  or buffering going on.

Writing to Western Digital USB 3 (spinning) external 4TB hard drive (incl. 64 MB internal cache) - benchmark-reported speeds
1.                     Writing raw binary data directly                                           103.66  MB/sec
2.                     Writing "simple single write" in HDF5                                     96.04 MB/sec
3.                     Writing "simple single write" in HDF5 with checksum          55.02 MB/sec
4.                     Writing      "        "    "  with checksum + compression L1        7.67 MB/sec
These results make a bit more sense than the MicroSD result. I can't find a claimed transfer speed for this hard drive on Western Digital's site.

IF these results are representative (a big "if") - then even a 4 TB spinning hard drive will be able to keep up with the PSWS data write rate. If anyone can confirm, reproduce, add to, or refute these results, I am most interested to know...

-73-
W. D. Engelke (Bill), Asst. Research Engr. AB4EJ
Center for Advanced Public Safety
Cyber Hall
The University of Alabama
Tuscaloosa, AL 35487
Desk: (205) 348-7244
Mobile: (205) 764-3099

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