On Thu, Feb 06, 2025 at 03:22:34PM +0100, Sebastian Andrzej Siewior wrote: > Then this feature adds 20us on top? The point has always been for the number to be < the observable scheduling latency. I'm not sure what that number is, and it is always hardware dependent. I measured it on a random test box when I did the prototype a long while ago, and ended up at 50us, but for all I know that machine was running a lockdep enabled kernel at the time (won't be the first and certainly won't be the last time I try and do a performance measurement on a debug kernel). That was not the important part -- but everybody fixates on the number, instead of the intent. I'm assuming you have a recent number around -- what's sane? 5us, less?
