Real-time Pulsar Software

Directories, environment, etc

• All source code, programs are installed in /opt/cbe-local/yuppi
• Currently code is owned by user yuppi, group evla_pulsar.
• Source /opt/cbe-local/yuppi/pulsar_env.csh or pulsar_env.bash to get environment variables and paths set up correctly.
  • Note, for the yuppi account this is done automatically upon login.
• The pulsar_env.*script also sets up a few useful paths in the following variables:
  • $PSR = the base dir for pulsar code, currently /opt/cbe-local/yuppi.
  • $PSRDATA = the base dir for pulsar data output, currently /lustre/evla/pulsar.
  • $PSRLOGS = the dir for log files, currently /lustre/evla/pulsar/log.

Starting up / Stopping

• These commands should be run while logged in to cbe-master as yuppi:
  • To run a command on all CBE nodes (via ssh): cbe_node_run (command).
  • To start the supervisord process control software on all nodes: cbe_node_run supervisord.
• These commands can be run as any user logged in to cbe-master:
  • To start the YUPPI status daemon on all nodes: yuppi_supervisor start_status.
  • To start the YUPPI observing software on all nodes: yuppi_supervisor start.
  • To stop the YUPPI observing software on all nodes: yuppi_supervisor stop.
  • To start the YUPPI status daemon on all nodes: yuppi_supervisor stop_status.
  • To open the monitor screen (on cbe-master, or any other system that can connect to cbe nodes): yuppi_status_client.

Files

• .evla and .vci files stored (at least for now) in /home/mchost/evla/scripts/test/realtimePulsar/
• Each process outputs its log file in /lustre/evla/pulsar/log/$HOSTNAME (also accessible via the $PSRLOGS environment variable).

Software Overview

• All programs described here run independently on each CBE node.
• Software block diagram and data/metadata flow in a single node:
  

supervisord

• Executable name: supervisord (daemon); supervisorctl (control interface)
• Source dir: $PSR/src/supervisor-3.1.0
• Online repository: http://supervisord.org/
• Description:
  • This is a third-party process control system.
  • We use it to start, stop and check status of the various YUPPI processes.
  • Configuration file is installed at $PSR/etc/supervisord.conf

yuppi_controller

• Executable name: yuppi_contoller.py
• Source dir: $PSR/src/EVLA_pulsars/controller
• Online repository: http://github.com/demorest/EVLA_pulsars
• Description:
  • This is a persistent process that listens for VCI or OBS multicast packets, and parses the XML contents.
  • When a matching VCI/OBS pair is found, it performs several actions, including:
    • Filling the status shared memory with relevant info about the observation (frequency, bandwidth, source name, VDIF thread IDs, etc).
    • Sending START or STOP to yuppi_daq_server.
    • Launching dspsr or digifil with appropriate options.
  • All actions are executed at the startTime specified in the OBS packet.

yuppi_daq_server

• Executable name: guppi_daq_server
• Source dir: $PSR/src/guppi_daq/src
• Online repository: http://github.com/demorest/guppi_daq
• Description:
  • This is a lightweight, persistent process listening for commands on the /tmp/guppi_daq_control FIFO.
  • When sent a START command, it launches a thread that reads VDIF data from the network, and organizes it into the databuf shared memory area.
  • Also compiles statistics about data loss, and puts this in the status shared memory.
  • Other commands accepted: STOP, MONITOR, and QUIT.

dspsr / digifil

• Executable name: dspsr or digifil
• Source dir: $PSR/src/dspsr
• Online repository: http://dspsr.sourceforge.net
• Description:
  • This is the main data processing program for pulsar modes. It reads data from the databuf shared memory, and writes PSRFITS files to $PSRDATA directory.
  • Both programs are part of the same package. dspsr does filterbank (splitting a "subband" into "channels"), coherent dedispersion and pulse period folding, while digifil does filterbank and time integration, producing search mode output.
  • This is not a persistent process, it is launched by yuppi_controller when a scan starts.
  • dspsr / digifil output currently appears in the yuppi_controller log file (but we may want to change this).

yuppi_status

• Executable name: yuppi_status_daemon.py (server), yuppi_status_client.py (client)
• Source dir: $PSR/src/EVLA_pulsars/status
• Online repository: http://github.com/demorest/EVLA_pulsars
• Description:
  • The server code runs on each node and makes the status shared memory contents available to remote clients via Pyro.
  • The client program reads several useful quantities from each node and compiles them into a single (curses-based) text display.
  • This is still very rudimentary and was put together quickly in order to have a easy way to keep tabs on all nodes at once while testing. It could grow into something more full-featured, or could be replaced with a different approach.