VEGAS Pulsar Project Meeting: 2016 March 21st 2:00 - 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 0.15


  • Jason, Richard, Justin, Ryan, Ray, John, Paul, Scott


BOF file status updates

Coherent Modes

Mode BOF File Status
c1500x4096 c1500x4096_x14_7_ss_2015_Dec_16_1447.bof Sim Teting
c1500x2048 c1500x2048_x14_7_2016_Mar_02_1218.bof Sim Testing
c1500x1024 c1500x1024_x14_7_2015_Jul_25_1525.bof Needs SS Build
c1500x0512 c1500x0512_x14_7_2016_Feb_24_1437.bof Sim Teting
c1500x0256 c1500x0256_x14_7_2016_Mar_04_1344.bof Sim Teting
c1500x0128 c1500x0128_x14_7_2016_Mar_05_1423.bof Sim Teting
c1500x0064 c1500x0064_x14_7_2016_Mar_09_0820.bof Sim Teting
c0800x4096 c0800x4096_x14_7_2016_Mar_09_1415.bof Sim Teting
c0800x2048 c0800x2048_x14_7_2016_Mar_09_1445.bof Sim Teting
c0800x1024 c0800x1024_x14_7_2016_Mar_09_1450.bof Sim Teting
c0800x0512 c0800x0512_x14_7_2016_Mar_14_1421.bof Sim Teting
c0800x0256 c0800x0256_x14_7_2016_Mar_10_1136.bof Sim Teting
c0800x0128 c0800x0128_x14_7_2016_Mar_10_1144.bof Sim Teting
c0800x0064 c0800x0064_x14_7_2016_Mar_11_0859.bof Sim Teting

Incoherent Modes

Mode BOF File Status
i1500x8192 i1500x8192_x14_7_2015_Jul_21_1543.bof Needs SS Build
i1500x4096 i1500x4096_x14_7_2015_Jun_26_0835.bof Needs SS Build
i1500x2048 i1500x2048_x14_7_ss_2015_Dec_15_1510.bof Sim Testing
i1500x1024 i1500x1024_x14_7_2015_Jun_26_1625.bof Needs SS Build
i1500x0512 i1500x0512_x14_7_2015_Jul_01_1649.bof Needs SS Build
i1500x0256 i1500x0256_x14_7_2015_Jul_17_0922.bof Needs SS Build
i1500x0128 i1500x0128_x14_7_2015_Jul_17_1605.bof Needs SS Build
i1500x0064 i1500x0064_x14_7_2015_Jun_01_1918.bof Needs SS Build
i0800x8192 i0800x8192_x14_7_2015_May_30_1752.bof Duplicate Pulse Signal; Needs SS Build
i0800x4096 i0800x4096_x14_7_2015_May_22_2349.bof Needs SS Build
i0800x2048 i0800x2048_x14_7_ss_2015_Dec_16_1028.bof Sim Testing
i0800x1024 i0800x1024_x14_7_2015_May_13_2000.bof Needs SS Build
i0800x0512 i0800x0512_x14_7_2015_May_17_2357.bof Needs SS Build
i0800x0256 i0800x0256_x14_7_2015_Jun_04_2301.bof Needs SS Build
i0800x0128 Incorrect Bandpass; Needs SS Build
i0800x0064 i0800x0064_x14_7_2015_May_30_1719.bof Incorrect Bandpass; Needs SS Build
  • Outstanding Issues
    • i0800x0064 and i0800x0128 modes have incorrect bandpass shapes
      • Seem to have excess power in higher channels relative to lower channels
      • Injected tone is showing up at correct frequency
      • Spurs are seen at Fs/4 on both SRBS and VEGAS
      • OGM/MMCM calibration should be OK
    • i0800x2048 shows a duplicate pulsed signal, almost as if folding period is twice what it should be
  • Randy working on adding SS support and correct bandpass saturation behavior, will continue builds off parent version

Low bandwidth modes

  • Current plan is to perform filterbank FFTs on GPU
    • Makes BOF file builds simpler
    • Requires CUDA development
    • Time series would be fed to HPC, which would perform PFB - corner turn - FFT - complex multiply - FFT - accumulate
      • Everything after corner turn exists in the coherent dedispersion algorithm
      • GPU code exists for PFB and corner turn in spectral line modes but needs to be merged with pulsar code


  • Coherent mode scans are failing to initialize in the simulator
    • Seems to be affect more modes
    • NETSTAT hangs in waiting, as if packets are now flowing
      • Randy and Jason confirm that packets do flow in initial BOF file tests
    • No obvious errors reported by Manager or Coordinator other than "vegas_hpc process taking too long to respond" and an aborted scan
      • We don't think this is an issue with the Manager itself. It seems more likely to be a problem with the BOFs or guppi_daq.
    • Trying to use tcpdump to inspect packets directly
      • Randy and Jason use udp_recv to look for packets and IDs, and these all seem to look OK
      • AP bandpass also looks OK
    • Jason suggests looking at 10Gbe reset
      • This could explain why packets might flow initially but then fail after a reset gets executed
    • Could also check that IP addresses
    • Needs to be fixed for testing purposes
  • Coordinator/Manager
    • Manager repeatedly prints a message regarding the IF Manager:

ParamRep::XDRserialize: No dd for id
RPCclient::rexec:RPC: Can't encode arguments
      • Related to communication between VegasManager and IFManager to get input sideband
        • Indicates a difference between ddl's in the IFManager and what VegasManager expects
        • Could happen if something was added to the IFManager that VegasManager doesn't know about
      • Doesn't seem to cause any failures but needs to be fixed, or else Messages gets constant errors
  • Configtool changes
    • Astrid still reports that VEGAS failed to balance when trying to adjust LBW gain. Still need to work on disabling this for pulsar modes.
    • Astrid still issues a warning about a discrepancy in the requested and actual IF rack power levels, though this did not cause a failure
  • Matrix HPC
    • No updates
  • Low Bandwidth Modes
    • Having trouble identifying resources from software and digital for this
    • Marty to talk to Ryan

GBT testing

  • Randy and Jason complete a large number of coherent mode BOFs with switching signal support. Ryan to test all of these with VEGAS hardware
  • Ryan to test spectral line modes using VEGAS software

Wideband AP

  • Vereese to have students working on things summer

VEGAS/DIBAS-style backend for FAST

  • Work progressing as independent project
  • NSF/AUI approved
  • Contract sent to FAST, waiting for signed copy

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

  • March 28

-- RyanLynch - 2016-03-21
Topic revision: r3 - 2016-03-22, RyanLynch
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