Problem:
RFM reads are slow. Rolf has said it should take 2-3 microseconds per read.
c1sus is taking about 7 microseconds per read, twice as slow as Rolf's claim.
Hypothesis:
The RFM card is in the IO chassis, and is sharing the PCIe bus with 4 ADC cards, 3 DAC cards, 4 BO cards, and a BIO card. Its possible this crowded bus is causing the reads to take even longer.
Test Results:
Compare read times between the c1sus computer, which has its RFM card in the IO chassis, to c1ioo, which has its RFM card in the computer.
c1ioo:
No RFM reads: 8 microseconds
3 RFM reads: 20 microseconds (~4 per read)
6 RFM reads: 32 microseconds (~4 per read)
c1sus:
No RFM read: 25 microseconds (bigger model)
1 RFM read: 33 microseconds (~8 per read)
3 RFM read: 45 microseconds (~7 per read)
6 RFM read: Over 62 microseconds, doesn't run.
Conclusion:
It looks like moving the RFM card may help by about a factor of 2 in read speed, although its still not quite what Alex and Rolf claim it should be.
The c1mcs and c1ioo models have been reverted to their normal operations.
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