VEGAS Pulsar Project Meeting: 2016 May 9th 2:00 - 3:00pm ET

Room / Connection Details

• GB-137 / Soc 280
• 192.33.117.12##7144
• 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

Present

• Randy, Jason, Ryan, Justin, Paul, Natalia

Agenda

BOF file status updates

Coherent Modes

• 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
    
    • 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

Incoherent Modes

• Outstanding Issues
  • All existing BOFs look good in simulator
  • Randy building i1500x0032 mode
    • Will require more detailed testing
    • Custom transform for channel ordering
      • Developed software level injection on per-channel basis to use for mapping
      • Seeing duplicale spikes in first 8 channels, still trying to track down
      • Still trying to map channels successfully
      • 1500 MHz build works, but no 1500 MHz synthesizer to test across the entire band
        • Test vector generator works
        • Tried merging into design with DSP blocks, 1500 MHz version seems to be working well
      • 800 MHz build is not working when basing off the 1500 MHz design

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

Fast4K and Fast8K Modes

• GUPPI only uses Fast4K for 100 MHz modes
  • Probably does not require a separate hardware mode
  • Action item: Discuss how to implement in software.

Software

• Configtool changes
  
  • GUPPI parfile is not being passed correctly with VPM branch
    • Instead of correct path, it appears that the beginning of a python dictionary is being passed (i.e., the parfile name begins with a '{')
  • VEGAS now balances without errors.
  • Analog filter rack power level targets set to 1 V only in dual backend pulsar mode
• Matrix HPC
  • • No updates
• Low Bandwidth Modes
• Manager maintenace
  • Scans occasionally abort due to 'HPC program taking too long to be ready'
    • Happens at beginning of scans
    • Occurs in dual backend and VEGAS only pulsar mode, as well as spectral line mode
    • Difficult to reliably reproduce. Sometimes scans run successfully.
    • Usually occurs right after a mode change. On the next attempt, scans tend to run. But even this is inconsistent.
    • Sometimes, splitting the 'Track' command into a separate scheduling block from the 'Configure' and 'Balance' commands helps. However, adding sleep statements to a single scheduling block before a Track does not seem to help.
    • Justin attempting to recreate in the simulator
      • John suggests checking nVidia driver versions on srbs and VEGAS
        • Not documented, but Joe had found a problem that was fixed using different nVidia flags
  • Manager core dumps when killed with SIGINT

GBT testing

• Last week we were able to do some tests with motion. Despite some problems with config tool and aborted scans, we were able to detect an MSP with VEGAS and GUPPI.
  • IF Manager reports a Sky frequency for GUPPI that does not equal the specified restfreq. This seems to happen with the VPM and release software branches. Is this understood?
  • Bandpass in GUPPI i0800x0064 channel mode did not reflect receiver response. This seemed to be the case with the VPM and release software branches. This mode is rarely used, but is this a known issue?

Wideband AP

• No updates

VEGAS/DIBAS-style backend for FAST

• Work progressing as independent project
• Ryan's trip scheduled for week of August 29

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

• TBD