Jenkins Page is Unresponsive and Performance Issues

I suspect that the high number of concurrent tasks is causing the Jenkins page to become unresponsive.


  • Jenkins version: 2.356
  • Single controller node with 64GB of RAM and 32-core CPU
  • Jenkins agents distributed across 80 PCs
  • Each PC runs only one process due to business requirements; no concurrent execution on a single PC
  • Each job has a long runtime: the shortest is about half an hour, and the longest takes approximately two days
  • Currently, there are not many plugins installed
  • Currently, I see that there are 104 concurrent tasks

Could the high number of concurrent tasks be the reason for the Jenkins page becoming unresponsive? Do I need to split into multiple controller nodes? What is the upper limit of tasks that a single controller node can support?

How many jobs and how many runs do you have on your controller? This determines the amount of memory you need.
You can see the heap usage under .../manage/systemInfo and the click on Memory Usage (if that is available on that old Jenkins).
CPU looks ok for that load.

Are all pages in Jenkins unresponsive or only the dashboard.

My Jenkins has 170 agents (almost all with a single executor) and most jobs run between 45min to 2 hours with a few jobs running up to 1 day. It runs in a docker container that has 80GiB memory and max heap of the jvm is set to 30GiB.

How are the settings for garbage collection? The wrong settings can have a severe impact on UI performance

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Thank you for your response. My total number of jobs is 1272, and currently, there are 108 jobs running. Most of the jobs are pipeline jobs, with each stage running from 15 minutes to 10 hours. Compilation and testing tasks are performed in different containers, primarily related to C++ and Python GPU testing. Each PC runs only one container. The entire Jenkins is unresponsive, not just a specific page. I have not specifically configured any garbage collection mechanism, so it should be using the default Jenkins settings.

Tuning Jenkins GC For Responsiveness and Stability with Large Instances gives good advice how to tune garbage collection for Jenkins.

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Thank you, Markus. I will follow the advice in the blog post and make the necessary changes to the garbage collection settings. I will monitor the performance for a while and see if it resolves the issue. Thanks again!

Which page is unresponsive? Generally multiple thread dumps taken over a few minutes can help see what’s causing it