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): > 1. Boot with kernel with the regression > 2. Do something that uses all cores, like compiling the Linux kernel > 3. 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
