[netperf-talk] Issues using parallel sessions of netperf

[Srikanth Sundaresan]

On 04/13/2011 05:06 PM, Rick Jones wrote:
> On Wed, 2011-04-13 at 16:57 -0400, Srikanth Sundaresan wrote:
>>
>> On 04/13/2011 04:54 PM, Rick Jones wrote:
>>> On Wed, 2011-04-13 at 16:31 -0400, Srikanth Sundaresan wrote:
>>>> Hi,
>>>> We are a group from Georgia Tech working on building a benchmarking
>>>> suite for home broadband internet. I've been testing netperf out as the
>>>> throughput tool.
>>>> In order to fully saturate the link, I'm running 3 netperf sessions
>>>> simultaneously. However, this causes 1 or two of the sessions to fail
>>>> with the following error:
>>>>
>>>> send_tcp_maerts: data recv error: Interrupted system call.
>>>> The output also has the following error: len was -1
>>>>
>>>> This only seems to occur on the TCP_MAERTS test; the TCP_STREAM test
>>>> seems to work fine (caveat: this is from a few dozen runs). Also, if I
>>>> run only 1 session, TCP_MAERTS works.
>>>>
>>>> Here's a sample output:
>>>> bin/netperf -l30 -P0 -fk -t TCP_MAERTS -p14536 143.215.129.122
>>>> bin/netperf -l30 -P0 -fk -t TCP_MAERTS -p14536 143.215.129.122
>>>> bin/netperf -l30 -P0 -fk -t TCP_MAERTS -p14536 143.215.129.122
>>>> send_tcp_maerts: data recv error: Interrupted system call
>>>>
>>>> In this example, one session failed. I tried opening 3 instances of
>>>> netserver on the server on 3 ports, but the same error occurred.
>>>>
>>>> I'm using netperf 2.4.5 on Linux 2.6.32. Please let me know if you need
>>>> more information. Any help would be greatly appreciated.
>>>
>>> My initial guess is that the end-of-test timer is firing when it was not
>>> expected to - perhaps the rate of data flow through the broadband link
>>> into the netperf(s) is such that the remote's close does not happen
>>> before the watchdog timer pops?
>>>
>> This testing is in an academic network (1Gbps connection between 2
>> servers). I was able to replicate it on a broadband link (though I only
>> ran the experiment a couple of times). Is there any more information
>> that I can give you that might help in debugging the issue?
> 
> How much time passes before the error message(s) appear?
> 

I'm running the test for 30 seconds. It occurs after 10s or so.

> happy benchmarking,
> 
> rick jones
>