hi, I've noticed something reasonably quirky with the AR9380 and later EDMA engine and I'd like to see if anyone else has seen it with ath9k.
It /looks/ like the TXOP gating for burstTime (ie, WMM bursts) is gated by a TX FIFO entry. Ie, if you queue 8 separate TX FIFO entries, each with a single MPDU, then you end up only getting one frame per burst window. For TDMA it shows up as frames only going out every time I push new frames into the FIFO. It's very .. odd. Now, if I try /really hard/ to keep pushing groups of frames into the FIFO (ie, a list of frames per TX FIFO slot) and I don't push a single frame here and there in, I get reasonably consistent 30mbit performance each way, which is what I'm expecting without A-MPDU or A-MSDU aggregation. But if I schedule say, 5 groups of 32 frames and then one frame, the PCU/QCU doesn't seem to grant that queue any more airtime until I push /another/ frame into the TX FIFO. Merely just hitting TXE for that queue doesn't work - I have to push in more frames to keep it immediately going rather than waiting for the next TXOP/gating time. So, I have some local hacks that only push groups of X (where X is 16 atm) frames into TX FIFO slots to keep the engine happy and will only push a shorter amount of frames into the TX FIFO if the FIFO itself is empty. That gets the performance on part with TDMA on AR5416/AR9280, which was the initial goal. Ok, so with all of the above - has anyone seen this kind of behaviour with ath9k? eg, doing lots of non-aggregate frames to some WMM burst queue, like voice or video? Thanks, -adrian _______________________________________________ ath9k-devel mailing list ath9k-devel@lists.ath9k.org https://lists.ath9k.org/mailman/listinfo/ath9k-devel
