> On Apr 13, 2021, at 5:22 PM, Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote: > >>> ms granularity seems very coarse grained for this. Surely >>> at some point of spinning you can afford a ktime_get? But ok. >> We are reading time when we are at the head of the (main) queue, but >> don’t have the lock yet. Not sure about the latency of ktime_get(), but >> anything reasonably fast but not necessarily precise should work. > > Actually cpu_clock / sched_clock (see my other email). These should > be fast without corner cases and also monotonic. I see, thanks. > >> >>> Could you turn that into a moduleparm which can be changed at runtime? >>> Would be strange to have to reboot just to play with this parameter >> Yes, good suggestion, thanks. >> >>> This would also make the code a lot shorter I guess. >> So you don’t think we need the command-line parameter, just the module_param? > > module_params can be changed at the command line too, so yes. Got it, thanks again. — Alex
