Transcript Data rate improvements

The e-EVN
Arpad Szomoru, JIVE
EVN CBD, Bonn, May 2012
SFXC developments
• Transition from MkIV to SFXC:
• Multi-epoch disk-based projects on MkIV: all done
• By session 1/2012, only 1 of 14 projects run on MkIV (probably the last)
• e-EVN continues to use MkIV for real-time correlation
• Phasing-out plan has been drafted
• Depends a bit on UniBoard first fringes
EVN CBD, Bonn, May 2012
UniBoard correlator
• UniBoard project will end June 30
• Several production runs (extra boards for ShAO, MPG, JIVE,
ASTRON)
• APERTIF shaping up: 80 to 100 boards needed
• Will be used as platform for AAVP computing
• Correlator development continuing
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End-to-end functionality demonstrated
Cross correlations with simulated data
Ironing out last issues wrt delay correction
Correlator control, status and error control, handling of output data
being addressed
• UniBoard2 funded, start July 1st
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Build on expertise of first project
Preserve personnel
Strong emphasis on power efficiency
28 nm available, 20 nm “soon”
Latest technology essential for SKA potential
Actual design may be delayed, in order to leapfrog one generation
of FPGA
EVN CBD, Bonn, May 2012
Scaling up SFXC
Current SFXC: 1 Gbps from 9 stations in real-time.
•Current SFXC: 256 cores, 2 racks, 9.5 kW
•SFXC replacement of MarkIV: 1024 cores, 8 racks, 38 kW
SFXC as a next generation EVN correlator: additional factor of 4 to go from 16 to 32
stations, and a factor of 4 to go from 128 to 512 MHz.
•SFXC as next generation EVN correlator: 16384 cores, 128 racks, 608 kW
Restricting the full 4GHz next generation case to 2-bit sampling, we'll need an
additional factor of 8 to go to 4 GHz.
•SFXC as 4GHz next generation EVN correlator: 131072 cores, 1024 racks, 4.9 MW
EVN CBD, Bonn, May 2012
And UniBoard
UniBoard replacement of MarkIV: 1 board, 400 W
Going to 32 stations and from 64 MHz to 512 MHz:
UniBoard as next generation EVN correlator: 8 boards, 3.2 kW
And finally going from 512 MHz to 4 GHz:
UniBoard as 4GHz next generation correlator: 64 boards, 25.6 kW
•Clearly very suitable as heavy-duty work-horse platform
•Challenge will be to implement extended functionality
• Pulsar gating, multiple phase centres
•SFXC and UniBoard: complement each other very well
• FPGA correlator will never be as flexible as software
• SFXC will never be as powerful as FPGA correlator
EVN CBD, Bonn, May 2012
NEXPReS
• Finally, some money has been distributed
• We have incredible stories to tell about bureaucracy
• Advancing in year 2
• Intensifying management role in Work Package 8
• Other work-packages doing OK
• Preparing 4Gbps real-time demo (On, Ef, Yb)
• Installing high-speed data servers, tests ongoing
• 4Gbps Bandwidth-on-Demand successfully demonstrated
• e-VLBI important driver in development of international standard
• Software, software, software
• NEXPReS board will meet in Copenhagen, June 20
• Preparing for new mid-term review
EVN CBD, Bonn, May 2012
SKA process
• PrepSKA formally ended
• Uneasy feeling about role of board, now Company has taken over
• JIVE currently involved in two consortia preparing EoI
• For stage one of SKA pre-construction engineering phase
• Provide expertise and feedback on various topics
• SKA Signal and Data Transport and Synchronization and Timing
• Network engineering, expertise with timing and frequency
• Low Frequency Aperture Array
• AAVP will use UniBoard: VHDL programming, correlator design
• Make sure experiences with AAVP feed back into design of UniBoard2
• Discussing participation in Central Signal Processor consortium
• UniBoard2 as a viable option for SKA Phase 1 correlator
EVN CBD, Bonn, May 2012
Some issues
•Divergence in digital backends
• DBBC, RDBE, KVAZAR backend, CDAS, DSN backend….
• Need to worry about compatibility
•Divergence in high-speed data recorders
• Mark5C, Mark6, NEXPReS FlexBuff (Aribox), X-Cube….
• Remarkably similar hardware
•Introduction of Mark6 in the EVN?
• Need to replace ~80% of EVN disk packs
• Or ~65% of disk capacity
• And basically gut all Mark5 units, install new backplane, motherboard….
•NEXPReS “philosophy”
• All VLBI (at least partly) e-VLBI
• Only ship data when necessary
EVN CBD, Bonn, May 2012
Increasing operational complexity
huib 08/06/10
EVN CBD, Bonn, May 2012
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Some more issues
• Many pieces of NEXPReS-related software in place
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Simultaneous recording/streaming at stations
Simultaneous recording/correlating at correlator (nearly available)
Tracking of disk packs, recordings on data buffers at various places
Automated system monitoring, generation of warnings (email, sms)
Enormously augmented functionality of Jive5AB: (partial) cornerturning, splitting of high-speed
data streams, not just limited to Mark5 platform anymore
Not all of this is used yet though…
• Use during NMEs, ftp fringe tests would be good start
• Need one control code for both e- and recorded VLBI
• Extension of Jive5AB code to full Haystack command set/responses
• Has been requested by TOG in past
• Return of e-MERLIN stations (fantastic news for users)
• 7 stations at a full 1Gbps? 7 Local recorders?
• Connectivity to Jb recently upgraded to 3Gbps
• Would benefit from scheme with fast buffering, partial real-time correlation, trickled e-transfer
• And how about new e-members like KVN?
EVN CBD, Bonn, May 2012