[Codel] iperf3 udp flood behavior at higher rates
dave.taht at gmail.com
Mon May 2 19:18:47 EDT 2016
to fork the fq_codel_drop discussion a bit...
I have up and running two new boxes that are my hope to be able to
test ath10k/ath9k hardware with, for this test, using one in the
middle as a router and a nuc i3 box as the server, all ports pure
ethernet... there's a switch in the way, too.
On tcp via netperf I get expected ~940 mbits.
On udp via iperf3 (again, all pure ethernet) - in neither case below
am I seeing any drops in the qdisc itself anywhere on the path, yet am
only achieving 500mbit.
1) Using the
iperf3 -c 172.26.16.130 -u -b900M -R -l1472 -t600
udp flood version, I get some loss on the initial burst, but none
*reported* after that, and peak at about ~500Mbits.
[ ID] Interval Transfer Bandwidth Jitter
[ 4] 0.00-1.00 sec 52.1 MBytes 437 Mbits/sec 0.037 ms
[ 4] 1.00-2.00 sec 54.3 MBytes 456 Mbits/sec 0.042 ms 0/38699 (0%)
[ 4] 2.00-3.00 sec 56.1 MBytes 470 Mbits/sec 0.030 ms 0/39933 (0%)
2) Flipping the sense of the test by getting rid of -R (from the nuc)
iperf3 -c 172.26.16.130 -u -b900M -l1472 -t600
I get on the other side a steady state throughput of a little over
520mbits (with 41% loss reported consistently)
[ 5] 37.00-38.00 sec 64.2 MBytes 539 Mbits/sec 0.026 ms
[ 5] 38.00-39.00 sec 62.8 MBytes 527 Mbits/sec 0.023 ms
[ 5] 39.00-40.00 sec 62.0 MBytes 520 Mbits/sec 0.033 ms
On the other:
[ 4] 77.00-78.00 sec 111 MBytes 929 Mbits/sec 78915
[ 4] 78.00-79.00 sec 103 MBytes 864 Mbits/sec 73371
[ 4] 79.00-80.00 sec 108 MBytes 907 Mbits/sec 77034
[ 4] 80.00-81.00 sec 107 MBytes 900 Mbits/sec 76423
[ 4] 81.00-82.00 sec 104 MBytes 875 Mbits/sec 74277
[ 4] 82.00-83.00 sec 113 MBytes 950 Mbits/sec 80666
Thinking that perhaps I was seeing loss in the rx ring, I used ethtool
to increase that from the default 256 to 4096...
only to hang things thoroughly... :( and I'm watching things reboot now.
Netperf does not have a multi-hop capable udp flood test (rick jones
can explain why... )
As I recall on this thread iperf3 was being run on a mac box as a
client, and I'll dig one up - but was it also osx on the other side of
And what other params would I tweak on linux to see a udp flood go faster?
Topology looks like this:
apu1 <-> apu2 <-> switch <-> nuc.
I could put another switch in the way, I am always nervous about
invoking hw flow control...
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