Re: ixg(4) performances

[Fredrik Pettai <pettai%nordu.net@localhost>]

On Jul 6, 2014, at 17:39 , Matthias Scheler <tron%zhadum.org.uk@localhost> 
wrote:
> 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.

Actually, it used to be ok performance, but after NetBSD 2.x - 3 (somewhere) 
release the performance went down.

http://bsd-beta.slashdot.org/story/04/05/03/2235255/netbsd-sets-internet2-land-speed-world-record

(I think the old Dell 2650 with the iNTEL 10 GB/s cards are still somewhere in 
the basement of LTU…)

/P