> -----Original Message----- > From: Aleksandr Loktionov <[email protected]> > Sent: Tuesday, October 6, 2026 7:40 AM > To: [email protected]; Nguyen, Anthony L > <[email protected]>; Loktionov, Aleksandr > <[email protected]> > Cc: Simon Horman <[email protected]> > Subject: [PATCH iwl-next v2 3/4] ixgbe: limit ITR decrease in latency mode to > prevent ACK overdrive > > From: Alexander Duyck <[email protected]> > > When operating in latency mode and the computed ITR is lower than the current > setting, the algorithm can reduce the interrupt rate too aggressively in a > single step. For a TCP workload this means the ACK stream (a > latency-sensitive, low-packet-rate workload) can drive the moderation down to > very high interrupt rates, starving CPU time from the sender side. > > After the speed-based ITR calculation is complete, check whether the result > is in latency mode and would decrease below the current setting. > If so, limit the decrease to at most IXGBE_ITR_ADAPTIVE_MIN_INC (2 us) per > update. This ensures the number of interrupts grows by no more than 2x per > adjustment step for latency-class workloads, dialling in > smoothly rather > than overshooting. > > Signed-off-by: Alexander Duyck <[email protected]> > Reviewed-by: Simon Horman <[email protected]> > Signed-off-by: Aleksandr Loktionov <[email protected]> > --- > drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 11 +++++++++++ > 1 file changed, 11 insertions(+)
Tested-by: Alexander Nowlin <[email protected]>
