Change Serial Channels during a running job
For the general usage of FPGA Serial Channels visit the main documentation page.
Sometimes a previously configured topology needs to be reconfigured, either because the topology was specified incorrectly or a different topology is required. This would entail saving the state of the job, canceling the running job and submitting a new job. By using the tool changeFPGAlinks mid-job you can change the topology on-the-fly without canceling the running allocation. This tool can also be used as a quick and handy way to visualize the current configuration with the FPGA-Link-GUI.
Usage
The tool currently only works directly on the FPGA-Nodes during a running job.
First submit a job like normal. You can either start with the first topology or omit it and start without any links:
fpga-tester@n2login1:~ $ srun -A pc2-mitarbeiter --constraint=emul -N 1 -p fpga -t 2:00:00 --fpgalink=ringO --pty zsh
Then load the module:
fpga-tester@n2fpga17:~ $ module load changeFPGAlinks
Then you can run changeFPGAlinks. Again either without a topology (This will only generate a overview and not change anything, useful for documenting) or specify a topology (With the known --fpgalink= format) to set the links:
fpga-tester@n2fpga17:~ $ changeFPGAlinks # Not changing anything, just checking Your current link-setup: n2fpga17:acl0:ch1-n2fpga17:acl1:ch0 n2fpga17:acl0:ch3-n2fpga17:acl1:ch2 n2fpga17:acl1:ch1-n2fpga17:acl0:ch0 n2fpga17:acl1:ch3-n2fpga17:acl0:ch2 To visualize this configuration click here: https://pc2.github.io/fpgalink-gui/index.html?import=n2fpga17%3Aacl0%3Ach1-n2fpga17%3Aacl1%3Ach0%20n2fpga17%3Aacl0%3Ach3-n2fpga17%3Aacl1%3Ach2%20n2fpga17%3Aacl1%3Ach1-n2fpga17%3Aacl0%3Ach0%20n2fpga17%3Aacl1%3Ach3-n2fpga17%3Aacl0%3Ach2%20 Your nodes in this Job (901745): n2fpga17 No configuration change requested. Goodbye.
Visualize here: Click!
Now the --fpgalink syntax is used to change the topology:
fpga-tester@n2fpga17:~ $ changeFPGAlinks --fpgalink=n00:acl0:ch0-n00:acl0:ch1 --fpgalink=n00:acl1:ch2-n00:acl1:ch3 --fpgalink=n00:acl1:ch0-n00:acl1:ch1 --fpgalink=n00:acl0:ch2-n00:acl0:ch3 # Change to custom topology Your current link-setup: n2fpga17:acl0:ch1-n2fpga17:acl1:ch0 n2fpga17:acl0:ch3-n2fpga17:acl1:ch2 n2fpga17:acl1:ch1-n2fpga17:acl0:ch0 n2fpga17:acl1:ch3-n2fpga17:acl0:ch2 To visualize this configuration click here: https://pc2.github.io/fpgalink-gui/index.html?import=n2fpga17%3Aacl0%3Ach1-n2fpga17%3Aacl1%3Ach0%20n2fpga17%3Aacl0%3Ach3-n2fpga17%3Aacl1%3Ach2%20n2fpga17%3Aacl1%3Ach1-n2fpga17%3Aacl0%3Ach0%20n2fpga17%3Aacl1%3Ach3-n2fpga17%3Aacl0%3Ach2%20 Your nodes in this Job (901745): n2fpga17 Started changing link-config with ID 0defb6f3-244f-415d-8372-5eaa324b4aa0 START: Thu Sep 16 11:44:41 CEST 2021 INFO: Request from user "fpga-tester" from job "901745" INFO: Nodelist of job: n2fpga17 INFO: Setting SPANK_FPGALINK0=n00:acl0:ch0-n00:acl0:ch1 INFO: Setting SPANK_FPGALINK1=n00:acl1:ch2-n00:acl1:ch3 INFO: Setting SPANK_FPGALINK2=n00:acl1:ch0-n00:acl1:ch1 INFO: Setting SPANK_FPGALINK3=n00:acl0:ch2-n00:acl0:ch3 Host list n2fpga17 Generated connections fpgalink n2fpga17:acl0:ch0-n2fpga17:acl0:ch1 fpgalink n2fpga17:acl1:ch2-n2fpga17:acl1:ch3 fpgalink n2fpga17:acl1:ch0-n2fpga17:acl1:ch1 fpgalink n2fpga17:acl0:ch2-n2fpga17:acl0:ch3 Topology configuration request accepted after 0.205315113068s To visualize this configuration click here: https://pc2.github.io/fpgalink-gui/index.html?import=n2fpga17%3Aacl0%3Ach0-n2fpga17%3Aacl0%3Ach1%20n2fpga17%3Aacl1%3Ach2-n2fpga17%3Aacl1%3Ach3%20n2fpga17%3Aacl1%3Ach0-n2fpga17%3Aacl1%3Ach1%20n2fpga17%3Aacl0%3Ach2-n2fpga17%3Aacl0%3Ach3%20
Visualize here: Click!
The topology gets changed to the requested one. Run the tool as often as you need topology changes. The next run will reflect the new topology.