On 2018-12-06 11:28:49 [+0100], Luca Abeni wrote: > Hi Sebastian, Hi Luca, > BTW, I tried to search for some document explaining what to enable and > what to disable in .config in order to get a well-performing RT > kernel, but I did not find anything useful... Does anyone have > recommendations about documents to read for correctly configuring a > PREEMPT_RT kernel? The obvious part is almost everything under "kernel hacking". So tracing hardly adds any overhead if not in use. CONFIG_HZ_PERIODIC should have less overhead compared to the NO_HZ versions. Usually you do something in a loop and a CPU hardly get idle. > Thanks for the patch! I am going to try it immediately. > BTW, playing with some options I discovered that if I add "nohz=off" > to the kernel commandline I get a maximum latency of about 150us when > using the i915 driver, and less than 100us when not using it. I am > going to test your patch, and to disable debugging and tracing... I'll > let you know the results. Is it better or worse with nohz=off? And do you get the backtrace? > Thanks again, > Luca Sebastian
