i.MX ProcessorsのトピックRe: iMX7 Ethernet - small packets

iMX7 Ethernet - small packets

urimashiach — Sun, 24 Jun 2018 09:15:19 GMT

Hello,

I'm using:

* i.MX 7Dual with the Atheros AR8033 Ethernet PHY.

* Linux based on branch imx_4.9.11_1.0.0_ga

The maximum rate for packet length of 64 Byte in UDP is ~36Mbits/sec.

The test is preformed with iperf3:

# iperf3 -c 192.168.11.218 -u -b 0 -l 64 -n 100M -i 10
Connecting to host 192.168.11.218, port 5201
[ 4] local 192.168.48.62 port 45709 connected to 192.168.11.218 port 5201
[ ID] Interval           Transfer     Bandwidth       Total Datagrams
[ 4]   0.00-10.00 sec 43.3 MBytes 36.3 Mbits/sec 709490
[ 4] 10.00-20.00 sec 43.1 MBytes 36.2 Mbits/sec 706380
[ 4] 20.00-23.17 sec 13.6 MBytes 36.0 Mbits/sec 222530
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval           Transfer     Bandwidth       Jitter    Lost/Total Datagrams
[ 4]   0.00-23.17 sec   100 MBytes 36.2 Mbits/sec 0.016 ms 44/1638400 (0.0027%)
[ 4] Sent 1638400 datagrams

Much better results for larger packets:

# iperf3 -c 192.168.11.218 -u -b 0 -n 1G -i 10
Connecting to host 192.168.11.218, port 5201
[ 4] local 192.168.48.62 port 33337 connected to 192.168.11.218 port 5201
[ ID] Interval Transfer Bandwidth Total Datagrams
[ 4] 0.00-10.00 sec 645 MBytes 541 Mbits/sec 82570
[ 4] 10.00-15.88 sec 379 MBytes 541 Mbits/sec 48510
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[ 4] 0.00-15.88 sec 1.00 GBytes 541 Mbits/sec 0.069 ms 0/131076 (0%)
[ 4] Sent 131076 datagrams

Is it a driver issue?

Thanks,

Uri

Re: iMX7 Ethernet - small packets

Bio_TICFSL — Wed, 27 Jun 2018 13:27:09 GMT

Hi Uri,

You are limitating the use of 100M and the other is a 1G:

1) iperf3 -c 192.168.11.218 -u -b 0 -l 64 -n 100M -i 10

2) iperf3 -c 192.168.11.218 -u -b 0 -n 1G -i 10

Regards

Re: iMX7 Ethernet - small packets

b36401 — Thu, 28 Jun 2018 05:27:47 GMT

Actually it is normal (and expected) situation when small packets performance is significantly less than big packets.
Maximum efficiency is achieved with largest allowed size.
And in case of minilal size the performance will be less in several times.
Please refer this article for an example values:
http://www.informit.com/articles/article.aspx?p=99812&seqNum=5

Have a great day,
Victor

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Re: iMX7 Ethernet - small packets

urimashiach — Thu, 28 Jun 2018 06:21:32 GMT

Hello Victor,

Please note that the article issue is TCP packets while in my question is about a UDP packets.

The acknowledgment is not relevant for UDP communication.

Please note that UDP packets were used in the provided iperf3 tests.

Thanks,

Uri

Re: iMX7 Ethernet - small packets

b36401 — Wed, 13 Feb 2019 01:41:44 GMT

Anyway it is expected that performance for small packets is significantly less than for big ones.