In HELP-24525, the Atlas profiler was marking updates to the systems collection as slow and the user wanted to confirm whether the durations seen were expected, but we don't currently have a performance test for the logical session cache refresh to get a baseline. The default refresh period is 5 minutes, and if a user creates a lot (1000s let's say) sessions in that time period then we'll be doing multiple writes to the sessions collection with batch sizes of 1000. It might be useful to get baseline numbers for how long we expect the refresh to take for a large number of sessions.