Re: Throughput regression with `tcp: refine TSO autosizing`
From: Michal Kazior <hidden>
Date: 2015-02-06 14:08:19
Also in:
linux-wireless
On 6 February 2015 at 14:40, Eric Dumazet [off-list ref] wrote:
On Fri, 2015-02-06 at 10:42 +0100, Michal Kazior wrote:quoted
The above brings back previous behaviour, i.e. I can get 600mbps TCP on 5 flows again. Single flow is still (as it was before TSO autosizing) limited to roughly ~280mbps. I never really bothered before to understand why I need to push a few flows through ath10k to max it out, i.e. if I run a single UDP flow I get ~300mbps while with, e.g. 5 I get 670mbps easily.For single UDP flow, tweaking /proc/sys/net/core/wmem_default might be enough : UDP has no callback from TX completion to feed following frames (No write queue like TCP) # cat /proc/sys/net/core/wmem_default 212992 # ethtool -C eth1 tx-usecs 1024 tx-frames 120 # ./netperf -H remote -t UDP_STREAM -- -m 1450 Socket Message Elapsed Messages Size Size Time Okay Errors Throughput bytes bytes secs # # 10^6bits/sec 212992 1450 10.00 697705 0 809.27 212992 10.00 673412 781.09 # echo 800000 >/proc/sys/net/core/wmem_default # ./netperf -H remote -t UDP_STREAM -- -m 1450 Socket Message Elapsed Messages Size Size Time Okay Errors Throughput bytes bytes secs # # 10^6bits/sec 800000 1450 10.00 7329221 0 8501.84 212992 10.00 7284051 8449.44
Hmm.. I confirm it works. However the value at which I get full rate on a single flow is more than 2048K. Also using non-default wmem_default seems to introduce packet loss as per iperf reports at the receiver. I suppose this is kind of expected but on the other hand wmem_default=262992 and 5 flows of UDP max the device out with 0 packet loss. Michał -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html