profiling: profile the UIS against the "complex" workflow

[oliver-sanders]

It would be good to profile the UI Server against the "complex" workflow running with something like a 1-5 second sleep for a few cycles to give us a good benchmark for expected resource usage.

Suggested experiment:

• Create an environment with no other Jupyter Server extensions (including Jupyter Lab).
  • So we are profiling Cylc, the whole Cylc and nothing but the Cylc.
• Clear your cylc-run directory (including stopped workflows).
  • So we are only measuring the impact of the one workflow.
• Profile the cylc gui command.
  • This will give us a memory watermark for an idle UIS.
  • Profile the default landing page (i.e. the Dashboard).
• Run the "complex" workflow (located in the Cylc 7 source code under etc/dev-suites).
  • I would pick a 1-5 second sleep (whatever works best for your platform, note the value you choose).
  • Start it --paused.
  • Set the final cycle point to a few cycles in the future (note the value you use).
  • Suggest profiling the workflow too so we can compare the memory fluctuation of the two side-by-side.
• Profile the cylc gui command.
  • Open a tree view on the "complex" workflow.
  • Unpause the workflow.
  • Let the workflow run to completion, give it a few seconds, then end the experiment.

Suggest using Memory Profiler on both the workflow and UIS and generating memory usage graphs for both. CPU usage is also of interest.