On Mon, Jun 14, 2021 at 07:21:55PM +0000, Adam Edge wrote:
Hello,
After I've upgraded from 5.7.11 (didn't have access to this machine for about 10 months) to 5.12.10, I've noticed that anytime I used all my cores to, for example, compile a project, the system would degrade significantly in performance and applications would start to stutter. Compiles are also about 3-4x slower on kernels with the regression vs. without. After debugging this for the past 24 hours or so, I've narrowed it down to a change between 5.7.19 and 5.8.1. Sadly, bisect does not help, because trying to run any of the 5.8 RC kernels causes the kernel to be stuck before init, without any apparent errors on the screen (and I don't have a serial cable to dump the kernel output to). I'm listing all the information I know and my system information below.
Reproduction steps (dunno if this helps, but):
- Boot with kernel with the regression
- Do something that uses all cores, like compiling the Linux kernel
- Observe long compile times and stuttering applications (which doesn't
happen even on full load with a working kernel)
Regression between kernel versions: 5.7 - working 5.7.11 - working 5.7.19 - working 5.8.1 - broken 5.8.18 - broken 5.12.10 - broken 8ecfa36cd4db3275bf3b6c6f32c7e3c6bb537de2 (master on 2021-06-13) - broken
Can you use 'git bisect' to track down the commit that caused the problem?
thanks,
greg k-h