On Tue, Jul 12, 2016 at 12:09 PM, Felix Fietkau <nbd@xxxxxxxx> wrote: > Hi, > > With Toke's ath9k txq patch I've noticed a pretty nasty performance > regression when running local iperf on an AP (running the txq stuff) to > a wireless client. Your kernel? cpu architecture? What happens when going through the AP to a server from the wireless client? Which direction? > Here's some things that I found: > - when I use only one TCP stream I get around 90-110 Mbit/s with how much cpu left over? > - when running multiple TCP streams, I get only 35-40 Mbit/s total with how much cpu left over? context switch difference between the two tests? tcp_limit_output_bytes is? got perf? > - fairness between TCP streams looks completely fine A codel will get to long term fairness pretty fast. Packet captures from a fq will show much more regular interleaving of packets, regardless. > - there's no big queue buildup, the code never actually drops any packets A "trick" I have been using to observe codel behavior has been to enable ecn on server and client, then checking in wireshark for ect(3) marked packets. > - if I put a hack in the fq code to force the hash to a constant value You could also set "flows" to 1 to keep the hash being generated, but not actually use it. > (effectively disabling fq without disabling codel), the problem > disappears and even multiple streams get proper performance. Meaning you get 90-110Mbits ? Do you have a "before toke" figure for this platform? > Please let me know if you have any ideas. I am in berlin, packing hardware... > > - Felix > -- > 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 -- Dave Täht Let's go make home routers and wifi faster! With better software! http://blog.cerowrt.org -- 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
