Re: [Bloat] [Codel] Network test tools for many parallel/concurrent connections?

[Rick Jones <rick.jones2@hp.com>]

On 05/15/2013 03:27 AM, Jesper Dangaard Brouer wrote:
> Hi Rick,
>
> Thanks for your input :-)
>
> I will definitely look into all these advanced options that netperf
> provide (which is didn't know of).  Netperf is definitely my favorite
> benchmarking tool, but I don't think it supports concurrent connections?

Not explicitly, no.  It is left as a scripting exercise to the 
benchmarker :)  The manual describes a few mechanisms for 
"synchronization" of tests to mitigate issues of skew error.  My 
"favorite" at this point is to post-process demo-mode output (which 
presumes reasonably well-synchronized clocks).

> (Perhaps a stupid question:) I'm curr using netperf 2.x, any reason I
> should switch to netperf 3.x ?

Netperf 3.x was something of an experimental dead-end.  It did have the 
idea of launching multiple threads in the netperf side, but retained the 
process-per-connection model on the netserver side.  I would suggest 
sticking with net[perf 2.x.

happy benchmarking,

rick

>
> Thanks you for developing netperf,

And to the *many* people who have contributed to it over the years.


> --Jesper
>
>
> On Tue, 14 May 2013 15:26:22 -0700
> Rick Jones <rick.jones2@hp.com> wrote:
>
>> It will not match what one can get from tcptrace, or commercial
>> solutions, but netperf can be asked to emit a number of potentially
>> "intersting" things.  Using the "omni output selectors" one can
>> request statistics for some interesting latencies:
>>
>> raj@tardy:~$ netperf -- -O ? | grep LAT
>> RT_LATENCY
>> MIN_LATENCY
>> MAX_LATENCY
>> P50_LATENCY
>> P90_LATENCY
>> P99_LATENCY
>> MEAN_LATENCY
>> STDDEV_LATENCY
>>
>> For a STREAM test those will be based on time in the send call.  For
>> a MAERTS test those will be time in the receive call.  For an RR test
>> those will be the round-trip times at the application layer.
>>
>> You can also ./configure --enable-histogram and if the verbosity is
>> set to 2 or more, a histogram of the distribution will be emitted
>> which will resemble:
>>
>> Histogram of time spent in send() call.
>> UNIT_USEC     :    0:    0:  434: 404912: 715323: 800663: 263305:
>> 9336: 2439: 1522
>> TEN_USEC      :    0: 2276:   41:   48:   97:   67:   79:   17:
>> 5:    7 HUNDRED_USEC  :    0:   28:    2:    2:    0:    2:    0:
>> 0:    1:    1 UNIT_MSEC     :    0:    3:    2:    0:    1:    0:
>> 1:    0:    0:    0 TEN_MSEC      :    0:    0:    0:    0:    0:
>> 0:    0:    0:    0:    0 HUNDRED_MSEC  :    0:    0:    0:    0:
>> 0:    0:    0:    0:    0:    0 UNIT_SEC      :    0:    0:    0:
>> 0:    0:    0:    0:    0:    0:    0 TEN_SEC       :    0:    0:
>> 0:    0:    0:    0:    0:    0:    0:    0
>>   >100_SECS: 0
>> HIST_TOTAL:      2200614
>>
>> when running under Linux, netperf also knows how to report the number
>> of TCP retransmissions encountered over the life of the data
>> connection:
>>
>> raj@tardy:~$ netperf -- -O ? | grep -i retran
>> LOCAL_TRANSPORT_RETRANS
>> REMOTE_TRANSPORT_RETRANS
>>
>> And if you want to have an idea of what each individual netperf was
>> doing in terms of mbit/s or trans/s over discrete points in its
>> lifetime, you can ./configure --enable-demo and it will emit interim
>> results at roughly the requested interval which can then be
>> post-processed.  An example of that being done can be found in
>> doc/examples/runemomniaggdemo.sh script and doc/examples/post_proc.py
>>
>> happy benchmarking,
>>
>> rick jones
>
>
>