On 26 June 2012 15:08, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote: > > On Tue, 2012-06-26 at 15:03 +0300, Eyal Shapira wrote: > > AVM FritzBox 7390 has a weird behaviour where once we enable > > U-APSD only on the VO AC it limits the rate of the packets > > it sends to 39Mbps and doesn't do AMPDU aggregation. > > This causes a big degradation in throughput obviously. > > It's important to note that this isn't related to PS and happens > > also when ACTIVE is forced. The traffic affected is sent in BE AC. > > Once legacy mode for all ACs is used the AP begins using higher rates > > as well as AMPDU aggregation which improves throughput significantly. > > > > In order to deal with this AP and potentially others switch to > > using legacy mode for all ACs by default. > > This actually somewhat makes sense if they have a bad aggregation > implementation, because you don't want VO to have latency, *especially* > not when uAPSD was enabled, indicating that you want VO-like low-latency > behaviour. > > I don't see why you're optimising for TPT on VO rather then latency? > The problem is that when we're requesting uAPSD on VO it messes up with traffic sent on the BE AC which isn't supposed to get affected but it does (probably a bug). The effect is that any traffic we're doing gets very low TPT. Apparently this AP is quite common in Germany and other places so we can't just ignore it. I was thinking that if someone wants uAPSD on the VO they can still set it from userspace through the nl80211. > > johannes > -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
