Niklas Cassel <niklas.cassel@xxxxxxxxxx> wrote: > When running iperf on ath10k SDIO, TX can stop working: > > iperf -c 192.168.1.1 -i 1 -t 20 -w 10K > [ 3] 0.0- 1.0 sec 2.00 MBytes 16.8 Mbits/sec > [ 3] 1.0- 2.0 sec 3.12 MBytes 26.2 Mbits/sec > [ 3] 2.0- 3.0 sec 3.25 MBytes 27.3 Mbits/sec > [ 3] 3.0- 4.0 sec 655 KBytes 5.36 Mbits/sec > [ 3] 4.0- 5.0 sec 0.00 Bytes 0.00 bits/sec > [ 3] 5.0- 6.0 sec 0.00 Bytes 0.00 bits/sec > [ 3] 6.0- 7.0 sec 0.00 Bytes 0.00 bits/sec > [ 3] 7.0- 8.0 sec 0.00 Bytes 0.00 bits/sec > [ 3] 8.0- 9.0 sec 0.00 Bytes 0.00 bits/sec > [ 3] 9.0-10.0 sec 0.00 Bytes 0.00 bits/sec > [ 3] 0.0-10.3 sec 9.01 MBytes 7.32 Mbits/sec > > There are frames in the ieee80211_txq and there are frames that have > been removed from from this queue, but haven't yet been sent on the wire > (num_pending_tx). > > When num_pending_tx reaches max_num_pending_tx, we will stop the queues > by calling ieee80211_stop_queues(). > > As frames that have previously been sent for transmission > (num_pending_tx) are completed, we will decrease num_pending_tx and wake > the queues by calling ieee80211_wake_queue(). ieee80211_wake_queue() > does not call wake_tx_queue, so we might still have frames in the > queue at this point. > > While the queues were stopped, the socket buffer might have filled up, > and in order for user space to write more, we need to free the frames > in the queue, since they are accounted to the socket. In order to free > them, we first need to transmit them. > > This problem cannot be reproduced on low-latency devices, e.g. pci, > since they call ath10k_mac_tx_push_pending() from > ath10k_htt_txrx_compl_task(). ath10k_htt_txrx_compl_task() is not called > on high-latency devices. > Fix the problem by calling ath10k_mac_tx_push_pending(), after > processing rx packets, just like for low-latency devices, also in the > SDIO case. Since we are calling ath10k_mac_tx_push_pending() directly, > we also need to export it. > > Signed-off-by: Niklas Cassel <niklas.cassel@xxxxxxxxxx> > Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx> Patch applied to ath-next branch of ath.git, thanks. 3f04950f32d5 ath10k: transmit queued frames after processing rx packets -- https://patchwork.kernel.org/patch/10422451/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
