We used 2.138.3 and now updated to 2.176.2. Both of them extremely slow when hitting 'configure' for any particular job we have. Web inspector in Chrome said that it was idle for 12 seconds and 8 seconds it presented the configurations...among other things rendered.
When running htop simultaneously in the host, I could see that the first CPU hit 120% and the second one over 9% during those 12 seconds Chrome was idle, and the process causing it was Jenkins related. So apparently it really takes 12 seconds for Jenkins to load configurations.
But it's not Jenkins version related. We also have 2.176.1 running with vast amounts of configurations. There loading an example configuration takes 5 seconds in total, of which it is idle 1.8 seconds, scripts for 1.7s, renders 800ms etc. These configurations aren't identical, so in our case it might be that we need to compare them. But be the reason for the difference whatever, loading configurations for several seconds is very slow.
Would it be possible to profile instance or to provide information to make the case reproducible? I do not see immediate root cause in the fixes