Andreas has sent us HAR files and thread dumps out-of-band to investigate
SSE channel registration takes long time
Optimize static resource fetch
Search API too slow for dashboard
initial search call extremely slow
Fetching favorited items for a user is very slow
Relates to search API performance issue.
Search API performance issue
Closing this issue. We have identified issues and opened tickets for relevant performance improvements in specific components: JENKINS-38251, JENKINS-38252, JENKINS-38253 and JENKINS-38087.
Thanks for filing this Andreas - fixing the performance issues above is a top priority for our team
see also: https://issues.jenkins-ci.org/browse/JENKINS-38335