[openib-general] Re: netperf over SDP bug

[Michael S. Tsirkin]

Quoting r. Grant Grundler <iod00d at hp.com>:
> Subject: netperf over SDP bug
> 
> Hi Michael,
> I'm trying to collect a full set of netperf TCP_STREAM over SDP for
> SVN r3547 on 2.6.13 kernel.  But some netperf runs get no throughput.
> Usually when sending 1k to 4k messages.  The same netperf parameters
> sing IPoIB seem to be working fine - just alot slower of course.
> Summary of all netperf over SDP runs is appended.
> 
> Sample commandline that got < 1Mb/s throughput is:
> LD_PRELOAD=/usr/local/lib/libsdp.so /usr/local/bin/netperf -p 12866 -l
> 60 -H 10.0.0.30 -t TCP_STREAM -T 1 -- -m 1024 -s 16384 -S 16384
> 
> I tried with some smaller -m parameters:
> 	512   -> ~270-280 Mb/s
> 	640   -> ~200-2100 Mb/s
> 	768   -> ~30-50 Mb/s
> 	896   -> ~2-6 Mb/s
> 
> CPU is essentially idle in the above 512-896 byte cases.
> Anything obvious I should be looking for or worth trying?
> 
> thanks,
> grant
> 
> #Recv   Send    Send
> #Socket Socket  Message  Elapsed
> #Size   Size    Size     Time     Throughput
> #bytes  bytes   bytes    secs.    10^6bits/sec
> 
> grundler <505>grep -h ' 60\.0. ' sdp*.out | sort -n -k 3

Interesting.
Things to try would be
- enable SDP debug, or event data path debug
- try running with oprofile, see what is CPU doing

-- 
MST