On 09.06.19 13:40, Marek Lindner wrote:
On Sunday, 9 June 2019 18:37:54 HKT Sven Eckelmann wrote:
No, we are not interested in rx rate for tx throughput estimations.
Before ruling rx out, can you explain your thinking behind this magic formula (if smaller compute sum and divide by 6):
Sorry, I should have provided way more context here.... The formula is min(tx/3,avg(rx,tx)/3), which is tx/3 for rx>tx
My thinking was 1. it should be lower than an expected throughput measurement (play it safe) 2. it should still be roughly in line with expected throughput as implemented elsewhere
I am testing this on devices with ath9k (2.4GHz) and ath10k (5GHz), so I was looking at the estimates I get from ath9k. Here is a dump from my home network on 2.4GHz/ath9k and what rx/3 would give us:
signal tx rx expect tx/3 min(tx/3,(rx+tx)/2/3) -77 13.0 43.3 6.682 4.333 -57 130.0 117.0 44.677 43.333 41.166 -53 117.0 130.0 42.388 39.0 -82 43.3 6.5 13.366 14.433 8.3 (!!!) -63 52.0 86.7 26.733 17.333 -58 130.0 173.3 29.21 43.333 !!! -82 6.5 43.3 2.197 2.166 -48 104.0 65.0 40.191 34.666 28.166 -69 57.8 13.0 20.49 19.266 11.8 -58 86.7 52.0 33.507 28.9 23.116 -61 57.8 72.2 29.21 19.266 -42 65.0 72.2 31.218 21.666 -58 52.0 1.0 37.994 17.333 8.833 -56 115.6 144.4 29.21 38.533 !!! -65 39.0 72.2 22.338 13.0 -55 58.5 72.2 29.21 19.5 -65 65.0 72.2 31.218 21.666 -59 86.7 117.0 35.705 28.9 -78 7.2 1.0 4.394 2.4 1.366 -22 65.0 72.2 31.218 21.666 -49 72.2 72.2 33.507 24.066 -68 13.0 21.7 8.879 4.333 -56 52.0 52.0 24.536 17.333 -66 43.3 52.0 24.536 14.433 -63 26.0 39.0 15.563 8.666 -42 65.0 58.5 31.218 21.666 20.583 -60 39.0 26.0 20.49 13.0 10.833 -63 28.9 58.5 17.852 9.633
Cases where the rx/tx estimate would be higher are marked with !!!.
Why bother and look at rx at all? Asymmetric routing should already work. I was bit concerned about highly asymmetric links, especially those where the path back might not work. It might not be worth it though.
Anyway, there are significant over-simplifications in here: - Is what I see here even representative / does it apply universally? - Is 5Ghz and 2.4GHz and their modes even comparable like this? Across drivers/chips?
Regards, René
if (sinfo.filled & BIT(NL80211_STA_INFO_TX_BITRATE)) {tx = cfg80211_calculate_bitrate(&sinfo.txrate);if (sinfo.filled & BIT(NL80211_STA_INFO_RX_BITRATE)) {rx =cfg80211_calculate_bitrate(&sinfo.rxrate);
if (rx < tx) {return (rx + tx) / 6;}}return tx / 3;}Thanks, Marek