On Sat, 12 Jul 2025 07:55:27 +0000 Dragos Tatulea wrote: > > The metrics make sense, but utilization has to be averaged over some > > period of time to be meaningful. Can you shad any light on what the > > measurement period or algorithm is? > > The measurement period in FW is 200 ms. SG, please include in the doc. > > > + changes = cong_event->state ^ new_cong_state; > > > + if (!changes) > > > + return; > > > > no risk of the high / low events coming so quickly we'll miss both? > Yes it is possible and it is fine because short bursts are not counted. The > counters are for sustained high PCI BW usage. > > > Should there be a counter for "mis-firing" of that sort? > > You'd be surprised how long the scheduling latency for a kernel worker > > can be on a busy server :( > > > The event is just a notification to read the state from FW. If the > read is issued later and the state has not changed then it will not be > considered. 200ms is within the range of normal scheduler latency on a busy server. It's not a deal breaker, but I'd personally add a counter for wakeups which did not result in any state change. Likely recent experience with constant EEVDF regressions and sched_ext is coloring my judgment.
