Having other large notebooks open while tab switching

[vidartf]

Problem

There were some recent issues where a change that gave a performance improvement when just 2 notebooks were open and switched between, it gave a performance penalty when multiple large files were open.

Proposed Solution

Keep multiple copies of large files open during benchmarking (maybe as a new class, maybe as a change to existing). As long has they have been displayed once before switching between tabs, all their elements (lumino and/or DOM) will still affect the performance. This should be closer to many symptomatic cases that users will see during their normal work.

[fcollonval]

~10 notebooks could be a good test

[krassowski]

I believe this will be addressed by https://github.com/jupyterlab/benchmarks/pull/143 which runs all the ui-profiler scenarios across three configurations:

• empty.ipynb - empty notebook
• div-span-svg-5k-each.ipynb - notebook with 5000 <div>, 5000 <span> and 5000 <svg> elements
• all-html-elements-100-each.ipynb - notebook with 100 elements for each known HTML tag