I was wondering what kind of readout speed should I expect through
katcp (python) and the tcpborphserver3 on a Roach1 (MMAP).
My simple spectrometer design has 16/channels per fft (48_34 bit) with
8 simultaneous paths (total of 128 channels). These get fed into 12
brams (32 bits 2^10 address). This gives me 64 integrations before
the address wraps. I'm trying to accumulate the data so that it reads
out at 100Hz so I have approximately 0.5 seconds to grab 32kb*12
(384kb) of data which is roughly 1Mb/s.
Using read('var', 4096) on each of the brams struggles (fails 10%
time) to make this 1Mb/s. Is this slow rate something to be expected
or do I have a coding error? I'm concerned because the correlator
version will have 32kb*48 outputs which if the speed scales will mean
the data collection time is too slow if I don't want to loose samples.
Ross
p.s. The MMAP improves the speed by about a factor of 2 over the
tcpborphserver2.
--
Ross Williamson
Research Scientist - Sub-mm Group
California Institute of Technology
626-395-2647 (office)
312-504-3051 (Cell)
