VEGAS Pulsar Project Meeting: 2016 May 16th 2:30 - 3:00pm ET

Room / Connection Details

  • GB-137 / Soc 280
  • 434-817-6443

Housekeeping Details

  • Main wiki page
  • gbsapp Mailing List
  • Location and regular date and time of meeting - agreed weekly on Mondays; GB-137 / Soc-280; 2-3pm ET
  • ETK codes:
    • Electronics: 432510.GB3015
    • Software: 893252.GB3015
    • Science: 432540.GB3015

Resource Allocations

LYNCH, Ryan 0.25


  • Justin, Randy, Richard, Ryan


BOF file status updates

Coherent Modes

Mode BOF File Status
c1500x4096 c1500x4096_x14_7_2016_Feb_19_1357.bof GBT Testing; >95% dropped packets in simulator
c1500x2048 c1500x2048_x14_7_2016_Mar_02_1218.bof GBT Testing; >90% dropped packets in simulator
c1500x1024 c1500x1024_x14_7_2016_Mar_16_1434.bof GBT Testing; 22% dropped packets in simulator
c1500x0512 c1500x0512_x14_7_2016_Feb_24_1437.bof GBT Testing; 6% dropped packets in simulator
c1500x0256 c1500x0256_x14_7_2016_Mar_04_1344.bof GBT Testing
c1500x0128 c1500x0128_x14_7_2016_Mar_05_1423.bof GBT Testing
c1500x0064 c1500x0064_x14_7_2016_Mar_09_0820.bof GBT Testing
c0800x4096 c0800x4096_x14_7_2016_Mar_09_1415.bof GBT Testing; occasional < 0.1% packet loss in simulator
c0800x2048 c0800x2048_x14_7_2016_Mar_09_1445.bof GBT Testing
c0800x1024 c0800x1024_x14_7_mt01_2016_Apr_01_1216.bof GBT Testing; MMCM calibration problems
c0800x0512 c0800x0512_x14_7_2016_Mar_14_1421.bof GBT Testing
c0800x0256 c0800x0256_x14_7_2016_Mar_10_1136.bof GBT Testing; MMCM calibration problems
c0800x0128 c0800x0128_x14_7_2016_Mar_10_1144.bof GBT Testing
c0800x0064 c0800x0064_x14_7_mt01_2016_Apr_01_1209.bof GBT Testing
  • Outstanding issues
    • Packet loss in high nchan 1500 MHz modes (expected)
    • MMCM calibration failing for zdok1 for c0800x1024 and c0800x0256
      • Low-level checks of MMCM calibration show glitches across all channels on the second ADC card.
      • Randy Suggested that placement of some blocks in these BOFs was not optimal. Two new builds to test this week.
    • 32-channel coherent modes
      • Continuing to have a problem in the structure of the PFB block, FFT block, or both, but difficult to identify which
      • Difficult to convince the existing blocks to use 32 channels
      • Single tones showing up in multiple bins with 4-bin spacing
        • Not a problem with the packet formating
        • When SNAP blocks and power blocks are injected, the 4-bin repeating shows up
        • Still want to try to use a test vector generator in place of the ADCs, but unlikely to be the problem as it would have shown up in other modes
      • Had tried to make a map for how injected signals map to output channels, but this is failing so long as a single tone shows up in multiple bins
      • One clock cycle short; In 64 channel-mode 8 clock cycles are needed to read out a spectra. In 32 channel mode, 4 clock cycles are needed, which would require speeding up processing of data through the rest of the design
        • This is still a problem but Randy thinks there is a workaround if the rest of the DSP chain works
        • Could try to use multiple memory banks to buffer/dump data

Incoherent Modes

Mode BOF File Status
i1500x8192 i1500x8192_x14_7_2016_Apr_18_0901.bof GBT Testing
i1500x4096 i1500x4096_x14_7_2016_Apr_18_0932.bof GBT Testing
i1500x2048 i1500x2048_x14_7_2016_Apr_18_1509.bof GBT Testing
i1500x1024 i1500x1024_x14_7_2016_Apr_18_1521.bof GBT Testing
i1500x0512 i1500x0512_x14_7_2016_Apr_18_1253.bof GBT Testing
i1500x0256 i1500x0256_x14_7_2016_Apr_19_0753.bof GBT Testing
i1500x0128 i1500x0128_x14_7_2016_Apr_20_1411.bof GBT Testing
i1500x0064 i1500x0064_x14_7_2016_Apr_19_0813.bof GBT Testing
i0800x8192 i0800x8192_x14_7_2016_Apr_19_0843.bof GBT Testing
i0800x4096 i0800x4096_x14_7_2016_Apr_19_1038.bof GBT Testing
i0800x2048 i0800x2048_x14_7_2016_Apr_19_1048.bof GBT Testing
i0800x1024 i0800x1024_x14_7_2016_Apr_19_1054.bof GBT Testing
i0800x0512 i0800x0512_x14_7_2016_Apr_19_1104.bof GBT Testing
i0800x0256 i0800x0256_x14_7_2016_Apr_19_1242.bof GBT Testing
i0800x0128 i0800x0128_x14_7_2016_Apr_19_1249.bof GBT Testing
i0800x0064 i0800x0064_x14_7_2016_Apr_19_1256.bof GBT Testing
  • Outstanding Issues
    • All existing BOFs look good in simulator
    • Randy building i1500x0032 mode
      • See above under coherent mode - same issues here

Low bandwidth modes

  • Randy has built 100 MHz and 200 MHz BOFs
    • All channelization will happen in software
    • Need to check software register compatability
      • These are VEGAS designs, so Randy and Jason have not added all the software registers used in pulsar modes (and some do not make sense for the LBW modes)
      • Requires discussion with Justin to make sure software knows how to interface with these designs
        • Action item: Justin to look at VEGAS LBW1 registers to determine which additional registers need to be added to the design, if any
          • Existing software registers for spectral line should be sufficient
          • Need to make sure manager knows which registers to look for in these modes and which not to look for
          • Any information that the HPC needs which isn't encoded into the FPGA designs will need to be supplied to the HPC programs from some other source
          • Action item: Randy to generate block diagrams
    • Would be good to have code that can look at the raw data stream, look for test tones, check ADC balancing
      • Joe may have some code to do this
      • Action item: Ryan to talk to Joe

Fast4K and Fast8K Modes

  • GUPPI only uses Fast4K for 100 MHz modes
    • Probably does not require a separate hardware mode
    • Action item: Ryan to talk to Jason about any existing builds that he and Arindam worked on.


  • Configtool changes
    • GUPPI parfile is now being passed correctly with VPM branch
    • Analog filter rack power level targets set to 1 V only in dual backend pulsar mode
  • Matrix HPC
    • Fully passed onto Ray
  • Low Bandwidth Modes
  • Manager maintenace
    • Manager was SEGFAULTing during operation
      • Traceback seemed to point towards the samplers
      • Ray suggested turning off some of the samplers but this seemed to cause a number of other problems
      • Unclear why the samplers would be causing a problem
    • Status writer was also causing SEGFAULTs
    • Manager handles mode changes without issue now in simulator

GBT testing

Wideband AP

  • No updates
  • Board populated, power supplies OK, found one faulty regulator but that has been fixed
  • Vereese interested in running electrical tests but this has not been done yet

VEGAS/DIBAS-style backend for FAST

  • Work progressing as independent project

Work for Next Quarter

  • Spectral line/VPM approaching point where everything needs to be merged back togehter
  • Request resources to fix outstanding spectral line issues, finish Matrix HPC and other outstanding software work
  • Spectral line work to be done
    • Add spike locations to FITS files
    • Balancing still confusing operators (IF balancing errors vs VEGAS internal errors)
    • Arm time bugs
    • 'HPC program taking too long to be ready' (maybe once per week)
    • Hangs in aborting (maybe once per week)
    • Integration vs scan length not consistent
    • Key words need to be cleaned up
  • Pulsar work to be done (assuming HBW/Manager works is completed)
    • Implement LBW modes
    • Complete Matrix HPC
    • Characterize astrophysical performance
    • Implement raw modes for high time resolution
    • Implement Fast4K/Fast8K modes in software

Multicasting for spectral line and pulsar modes

  • Modifications to ROACH configuration and net task must bind to a multicast group instead of a specific host
    • All the 10-gig addresses on the ROACH would be multicast groups, and config will be told which to bind to
    • Some changes to net task code (in VEGAS HPC and guppi_daq code) to initialize sockets

Date / Time of Next Meeting

  • June 13
-- RyanLynch - 2016-06-06
Topic revision: r2 - 2016-06-06, RyanLynch
This site is powered by FoswikiCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding NRAO Public Wiki? Send feedback