On Thu, 6 Jul 2023 01:44:49 +0000 Wei Fang wrote: > > But you shouldn't restart the queue for a single packet either. > > Restarting for a single packet wastes CPU cycles as there will be much more > > stop / start operations. Two large packets seem like the absolute minimum > > reasonable wake threshold. > > > > Setting tx_stop_threshold to MAX_SKB_FRAGS doesn't seem right either, as > > you won't be able to accept a full TSO frame. > > > Maybe I should keep the tx_stop_threshold unchanged, so that the queue is > to be stopped if the available BDs is not enough for a full TSO frame to be attached. > And then just change tx_wake_threshold to tx_stop_threshold + 1, which I think it's > more reasonable. How about at least tx_stop_threshold + 2 * MAX_SKB_FRAGS ? If a queue of hundreds of entries is overflowing, we should be able to apply a hysteresis of a few tens of entries. Do you see a difference in drops? The packets from the stack should preferably stay in the qdiscs instead of the driver queue, where AQM and scheduling can be applied.
