Hi everyone,
I am experiencing a significant performance degradation after upgrading my kernel from version 6.6 to 6.7 and would appreciate any insights or suggestions. I have reported the issue here, but I am still looking forward to getting more feedback on this issue to see if it affects others as well.
Problem Description:
I am running a simulation application where most of the threads are using real-time scheduling (SCHED_RR), and the threads of a model are using SCHED_DEADLINE. After upgrading the kernel, I noticed that the execution time of my model has increased from 4.5ms to 6ms
What I Have Done So Far:
- I found this bug report and reverted the commit efa7df3e3bb5da8e6abbe37727417f32a37fba47
mentioned in the post. Unfortunately, this did not resolve the issue. - I performed a git bisect and found these two commits related to scheduling (RT and deadline),
612f769edd06a6e42f7cd72425488e68ddaeef0a
5fe7765997b139e2d922b58359dea181efe618f9
After reverting these two commits, the model execution time improved to around 5 ms. - I revert two more commits, and the execution time is back to 4.7ms
63ba8422f876e32ee564ea95da9a7313b13ff0a1 [deadline server]
efa7df3e3bb5da8e6abbe37727417f32a37fba47
Questions:
- Has anyone else experienced similar performance degradation after upgrading to kernel 6.8?
- Can anyone explain why these two commits are causing the problem? I am not very familiar with the kernel code and would appreciate any insights.
- Are there any additional settings or configurations I need to apply when using kernel 6.8 to avoid similar issues?
Additional Details:
- CPU: AMD Ryzen Threadripper 3970X
- Operating System: Ubuntu 24.04
Thanks again for any insights or suggestions