hi tom,
for a 1400 MHz bandwidth single pol, you need
one roach and one 3 Gsps ADC board for pulsar/transient
search machine and kurtosis spectrometer.
for coherent dedispersion pulsar timing and for seti,
you could use the same system to break the 1400 MHz
band into sub-bands and send the sub-bands to a bank of GPU/CPU units.
each GPU/CPU can handle 200 MHz bandwidth, single pol.
if you have more than 4 CPU/GPU units, then you need a 10Gbe switch,
because roach only has four 10Gbit ports.
if you want 8 GPU/CPU units, to handle 1600 MHz single pol,
then it might be slightly cheaper to split the band into two 800 MHz chunks,
and use a pair of roaches, rather than purchasing a 12 port switch
and a single roach and a 10Gbe switch.
dan
On 1/29/2010 4:17 PM, Tom Kuiper wrote:
Dan Werthimer wrote:
each GPU can handle 100 to 200 MHz dual pol depending on whether
you are doing coherent dedispersion (timing), or spectroscopy
(searching).
matthew and jonathan are the experts at reading data from ibob/roach and
using CPU cluster to do pulsar/transient search.
john ford, paul demorest, scott ransom et al are the experts at using
ibob/bee2
to packetize data (800 MHz dual pol) for GPU based pulsar cluster
(see their fantastic GUPPI instrument).
We could have up to 1400 MHz at once, 8200-8600 and 31,500-32,500 MHz
but I think only one polarization. I saw that John Ford is using 8
GPUs for 800 MHz. Can you get several GPUs on the single bus of a
multi-core host or does that cause too much of a bottle-neck? I also
should think about doing the various piggy-back tasks in parallel.
I'm guessing that setispec on a ROACH is a tight fit. How about two?
The kurtosis is a very light task, I think, so can some of the
left-over resources be used to expand the SETI bandwidth or refine the
resolution?
Anyway, for now it's some high-level wishing so I'll scope one unit at
three dual-channel ADCs, three ROACHes, two 4 core hosts, and 8 GPUs.
Does that seem reasonable? About $40K? (We have to pay Xilinx :-( .)
Thanks for your help
Tom
