[netperf-talk] Help me to understand the results

[Rick Jones]

Steevan Rodrigues wrote:
> Hi,
> 
> I am newbie to netperf.
> I ran following command
> $ /usr/local/bin/netperf -l 5 -H 192.168.11.207 -t TCP_STREAM -c LOC_CPU 
> -C REM_CPU -i 10,2 -I 95,3 -- -m 1 -s 32768 -S 32768
> 
> And obtained following output (please see below). Can you please explain 
> me following ?
> 1) Why there is a warning about desired "Confidence level" ?

http://www.netperf.org/svn/netperf2/trunk/doc/netperf.html#index-g_t_002dI_002c-Global-26

> 2) When I include -c LOC_CPU  -C REM_CPU  I get  details about 
> "utilization" and "Service Demand" . What do they represent ?
> Do they represent local and remote CPU utilization ?

I suspect there has been some cut-and-paste confusion from a script somewhere as 
I would expect that to be $LOC_CPU and $REM_CPU.  Regardless the -c option 
requests measurement of local CPU utilization, -C requests measurement of remote 
CPU utilization.

http://www.netperf.org/svn/netperf2/trunk/doc/netperf.html#CPU-Utilization
http://www.netperf.org/svn/netperf2/trunk/doc/netperf.html#index-g_t_002dc_002c-Global-18

> 3) How max and min number of iterations are actually used ?

See the URL in the answer to 1.

> 4) Actually I want to measure throughput vs CPU Load for my system.
>    What is the best command for the above purpose ?

Are you trying to say you want to measure what throughput can be achieved at 
discrete levels of CPU utilization?   That may be something of a challenge.

It may be possible to measure CPU utilization at a given throughput level via:

http://www.netperf.org/svn/netperf2/trunk/doc/netperf.html#index-g_t_002dw_002c-Global-39
http://www.netperf.org/svn/netperf2/trunk/doc/netperf.html#index-g_t_002db_002c-Global-16

However, achieving a given level of throughput can be accomplished with more 
than one set of values for -b and -w, which may affect the CPU utilization. 
Toss-in the effect of the various values of the -m test-specific option and one 
is really talking about a rather large space.

> 5) Do I need to use a crossover cable for the test setup ?

1GbE and later networking does not require a cross-over cable.  100BT and below 
does.

> 6) Can I have multiple servers and one client ? Or multiple client and 
> one server setup ?

http://www.netperf.org/svn/netperf2/trunk/doc/netperf.html#Using-Netperf-to-Measure-Aggregate-Performance


> ==================================================
> TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.11.207 
> (192.168.11.207) port 0 AF_INET : +/-1.500% @ 95% conf.
> !!! WARNING
> !!! Desired confidence was not achieved within the specified iterations.
> !!! This implies that there was variability in the test environment that
> !!! must be investigated before going further.
> !!! Confidence intervals: Throughput      : 1.164%
> !!!                       Local CPU util  : 0.000%
> !!!                       Remote CPU util : 56.955%
> 
> Recv   Send     Send                                         
> Utilization       Service Demand
> Socket Socket  Message  Elapsed                     Send     Recv     
> Send    Recv
> Size     Size     Size           Time     Throughput    local    
> remote   local   remote
> bytes    bytes   bytes         secs.    10^6bits/s      % S      % 
> S      us/KB   us/KB
> 
>  65536  65536      1             5.00          9.46        100.00   
> 59.60    865.994  516.212
> ==============================================================
> 
> Thanks for your help,
> Steevan
> 
> 
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