KAGRA/Subgroups/CAL/GstLAL/tutorials/step12

Step 12: Link the shared memory to remote host

To read and write channel data from and to the shared memory, please refer step10 and step11
Here we try to link the channel data in shared memory at CAL low-latency machine to the DMG machine
We can use "framelink" program in GDS (gds-2.18.7/Utilities/FrUtils/framelink.cc)
Check the existing shared memory partition with "smlist" and kill it with "smkill" if it already exists

   1 part = options.partition
   2 lbuf = options.lbuf
   3 port = ':'+options.port
   4 
   5 sl = commands.getoutput('smlist')
   6 ss = sl.split('\n')
   7 
   8 if len(ss) > 1:
   9     for s in ss[1:]:
  10         cc = s.split()
  11         if cc[1] == part:
  12             print 'Killing the current partition:',cc[1]
  13             os.system('smkill '+cc[1])

Create a shared memory with specified buffer length, which should be large enough compared with the frame file data size

   1 print 'Creating a new partition:',part,'with lbuf=',lbuf
   2 os.system('smcreate '+part+' -lbuf '+str(lbuf))
   3 os.system('smlist')

Run "framelink" with either receive or push mode

   1 opt = ''
   2 if options.debug:
   3     opt = ' --verbose /dev/stdout --debug 1000'
   4 
   5 print 'Starting framelink...'
   6 
   7 if options.mode == 'receive':
   8     os.system('framelink'+opt+' receive 0.0.0.0'+port+' '+part)
   9 
  10 else:
  11     os.system('framelink'+opt+' push '+part+' '+options.host+port)

The python scripts are available at git repository

> kagra-cal/Observation/Phase1/tutorials/flink --help
Usage: flink [options]

Options:
  -h, --help        show this help message and exit
  --mode=mode       Set the operation mode, either from "receive" or "push".
  --partition=name  Set the name of the shared memory partition to write to.
  --host=host       Set the host name
  --port=port       Set the port number (default= 23232)
  --lbuf=size       Set the shared memory buffer size (default= 200000)
  --debug           Show debug messages

Here is an example to send the shared memory from the CAL machine to DMG machine
At the DMG machine, start the receiver server

> kagra-cal/Observation/Phase1/tutorials/flink --mode=receive --debug
Killing the current partition: KGR_hoft
Creating a new partition: KGR_hoft with lbuf= 200000
  id      name        nBuf   lBuf     nTotal
  32  KGR_hoft          4    200000         0

Starting framelink...
2018.08.21-08:27:39 Look up peer: 0.0.0.0:PORT
2018.08.21-08:27:39 Starting framelink: $Id: framelink.cc 7922 2017-08-03 00:14:52Z john.zweizig@LIGO.ORG $
2018.08.21-08:27:39 arguments are: --verbose /dev/stdout --debug 1000 receive 0.0.0.0:PORT KGR_hoft
2018.08.21-08:27:39 Verbose logging enabled to: /dev/stdout
2018.08.21-08:27:39 Binding socket to server address: 0.0.0.0
2018.08.21-08:27:39 Listening to server socket
2018.08.21-08:27:39 Waiting for client connection

At the CAL machine, start the pusher client

> kagra-cal/Observation/Phase1/tutorials/flink --mode push --host HOSTNAME --debug
Creating a new partition: KGR_hoft with lbuf= 200000
  id      name        nBuf   lBuf     nTotal
  32  KGR_hoft          4    200000         0

Starting framelink...
2018.08.21-08:33:43 Look up peer: HOSTNAME:PORT
2018.08.21-08:33:43 Starting framelink: $Id: framelink.cc 7922 2017-08-03 00:14:52Z john.zweizig@LIGO.ORG $
2018.08.21-08:33:43 arguments are: --verbose /dev/stdout --debug 1000 push KGR_hoft HOSTNAME:PORT
2018.08.21-08:33:43 Verbose logging enabled to: /dev/stdout
2018.08.21-08:33:43 Connecting to server: HOSTNAME
# Connected to: HOSTNAME
2018.08.21-08:33:43 framelink: Attaching consumer to partition KGR_hoft

At the DMG machine, it shows that the connection is established

2018.08.21-08:28:53 Client connected
2018.08.21-08:28:53 Keep-alive set
2018.08.21-08:28:53 framelink: Attaching producer to partition KGR_hoft
2018.08.21-08:29:53 framelink: Waiting for frame from 0.0.0.0

At the CAL machine, run "dpush" as in step 10 you can put a channel data into the shared memory

> kagra-cal/Observation/Phase1/tutorials/dpush --debug --shared-memory-partition=KGR_hoft
Opening partition KGR_hoft for output.
Opened frame file: 1sec/K-K1_TEST-1209288320-1.gwf
Read frame: file-length/rc 68771 / 68771
Opened frame file: 1sec/K-K1_TEST-1209288321-1.gwf
Waiting 999874usec.
Read frame: file-length/rc 65135 / 65135
Opened frame file: 1sec/K-K1_TEST-1209288322-1.gwf
Waiting 999564usec.
Read frame: file-length/rc 66984 / 66984
Opened frame file: 1sec/K-K1_TEST-1209288323-1.gwf
Waiting 999553usec.
...

At the CAL machine, you can check that the frame data is sent to the DMG machine

1218875715 get 1209288320 68771 OK.
2018.08.21-08:34:57 sent header block, len, gps, time = {0, 68771, 1209288320, 1}
1218875715 put 1209288320 68771 OK.
1218875716 get 1209288321 65135 OK.
2018.08.21-08:34:58 sent header block, len, gps, time = {1, 65135, 1209288321, 1}
1218875716 put 1209288321 65135 OK.
1218875717 get 1209288322 66984 OK.
2018.08.21-08:34:59 sent header block, len, gps, time = {2, 66984, 1209288322, 1}
1218875717 put 1209288322 66984 OK.
1218875718 get 1209288323 63983 OK.
2018.08.21-08:35:00 sent header block, len, gps, time = {3, 63983, 1209288323, 1}
...

At the DMG machine, you can check that the frame data is received from the CAL machine

2018.08.21-08:34:57 received header block, len, gps, time = {0, 68771, 1209288320, 1}
2018.08.21-08:34:57 Data length inferred from first block. dt = 1
1218875715 get 1209288320 68771 OK.
1218875715 put 1209288320 68771 OK.
2018.08.21-08:34:58 received header block, len, gps, time = {1, 65135, 1209288321, 1}
1218875716 get 1209288321 65135 OK.
1218875716 put 1209288321 65135 OK.
2018.08.21-08:34:59 received header block, len, gps, time = {2, 66984, 1209288322, 1}
1218875717 get 1209288322 66984 OK.
1218875717 put 1209288322 66984 OK.
2018.08.21-08:35:00 received header block, len, gps, time = {3, 63983, 1209288323, 1}
1218875718 get 1209288323 63983 OK.
1218875718 put 1209288323 63983 OK.
2018.08.21-08:35:01 received header block, len, gps, time = {4, 65568, 1209288324, 1}
...

KAGRA/Subgroups/CAL/GstLAL/tutorials/step12 (last edited 2018-08-21 20:34:39 by SadakazuHaino)