Mellanox MT25418 performance IPOIB?

Karl Pielorz kpielorz_lst at
Thu Apr 17 09:10:43 UTC 2014

--On 16 April 2014 14:28:37 +0200 Stig Inge Lea Bjørnsen 
<stiginge at> wrote:

> You could try to use Infiniband in datagram mode, recompile without the
> IPOIB_CM option.

Ok, same boxes - I just removed IPOIB_CM out of the kernel config and 
recompiled / installed it.

iperf now consistently returns:

[  3] local port 37715 connected with port 5001
[ ID] Interval       Transfer     Bandwidth
[  3]  0.0-10.0 sec  8.71 GBytes  7.46 Gbits/sec

> The maximum MTU will then be 4092, but it might default to 2044. I run
> OpenSM on both machines and set the MTU explicitly:

Yes, mtu defaulted to 2044 - raising it to 4092 actually causes a loss of 
.5-1Gbit with iperf (obviously not 'real world') - but at leas I can now 
try and use the stuff with real world (now it's returning more than a few 
hundred kilobytes a second!).

> The bandwidth reported by iperf is ~7.5 Gbits/sec in both directions.

Same as here then.

Thanks for your email!



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