Hi Thomas, On Mon, Aug 03, 2020 at 12:49:36PM +0200, Thomas Gleixner wrote: > Kurt, > > Kurt Kanzenbach <kurt.kanzenb...@linutronix.de> writes: > > On Thu Jul 30 2020, Vladimir Oltean wrote: > > OK. I've reproduced it on a Marvell Armada SoC with v5.6 mainline. See > > splats below. Running with irq time accounting enabled, kills the > > machine immediately. However, I'm not getting the possible deadlock > > warnings in 8250 as you did. So that might be unrelated. > > > > Unfortunately I have no idea what to debug here. > > lets look at the facts we have so far. > > 1) When irq accounting is disabled, RT throttling kicks in as > expected. > > 2) With irq accounting the RT throttler does not kick in and the RCU > stall/lockups happen. > > Not much, but there is clearly interaction between irq time accounting > and scheduler accounting. > > Can you please reduce /proc/sys/kernel/sched_rt_runtime_us in steps of > 50000? At least in theory, reduction should bring the throttling back. > > Thanks, > > tglx >
We already know from my original report that reducing sched_rt_runtime_us to 80% (800000) gives us a stable system. https://lkml.org/lkml/2020/6/4/1062 What is this telling us? Thanks, -Vladimir
