On Fri, Jul 04, 2014 at 02:43:19PM +0000, Emmanuel Dreyfus wrote:
> I quote myself here:
>
> On Wed, Jul 02, 2014 at 02:05:53PM +0000, Emmanuel Dreyfus wrote:
> > TCP connection established.
> > Packet size 1k bytes: 114938 KByte/s Tx, 114816 KByte/s Rx.
> > Packet size 2k bytes: 114924 KByte/s Tx, 114868 KByte/s Rx.
> > Packet size 4k bytes: 114871 KByte/s Tx, 114901 KByte/s Rx.
> > Packet size 8k bytes: 114877 KByte/s Tx, 114900 KByte/s Rx.
> > Packet size 16k bytes: 114882 KByte/s Tx, 114914 KByte/s Rx.
> > Packet size 32k bytes: 114881 KByte/s Tx, 114905 KByte/s Rx.
>
> ioperf reports awful perfs. But netperf says:
>
> root@saccharose# netperf -H 10.103.101.117
> TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.103.101.117
> (10.103.101.117) port 0 AF_INET
> Recv Send Send
> Socket Socket Message Elapsed
> Size Size Size Time Throughput
> bytes bytes bytes secs. 10^6bits/sec
>
> 32768 32768 32768 10.01 1152.76
>
> This look much better: maximum bandwith is 1200 Mb/s as I understand.
>
> How can this be explained?
Probably by a various factors:
1.) Lack of SMP scalabity in the network stack.
2.) No MSIE-X support.
3.) No RSS support in the driver.
You will also struggle to sature a 10Gb/s link with a single TCP connection
in general.
Kind regards
--
Matthias Scheler https://zhadum.org.uk/
