[etherlab-users] Data logging service dropping data

[Richard Hacker]

Can you find anything in the logs for dlsd?

Am 09/09/2013 08:04 PM, schrieb Johnathan Van Why:
> On Mon, Sep 9, 2013 at 7:39 AM, Richard Hacker <ha at igh-essen.com> wrote:
>>
>> Are you using a multi-processor system? If so, can try using HPET (although this timing system is buggy by design - was developed together with Microsoft ;) )
>
> I switched to the HPET, and it still drops data.
>
> Thank You,
> Johnathan Van Why
> Dynamic Robotics Laboratory
> Oregon State University
>
>> Am 09/06/2013 09:25 PM, schrieb Johnathan Van Why:
>>
>>> On Thu, Sep 5, 2013 at 11:38 PM, Richard Hacker <ha at igh-essen.com> wrote:
>>>>
>>>> What is you underlying real-time operating system?
>>>
>>>
>>> I am doing my testing on Linux, patched with PREEMPT_RT for realtime.
>>>
>>>> The DLS has a problem when the RT system influences time on the PC. This has
>>>> been experienced with RTAI.
>>>>
>>>> Ways to fix it? Watch the system's clock while the control system is loaded
>>>> and make sure it is not "pulled" in any way.
>>>
>>>
>>> I have confirmed that there is no clock drift (note: the kernel's
>>> clocksource is the TSC). I disabled NTP and re-ran the test, with the
>>> same results (lost data and no clock drift).
>>>
>>> Do you have any other ideas?
>>>
>>> Thank you for the help,
>>> Johnathan Van Why
>>> Dynamic Robotics Laboratory
>>> Oregon State University
>>>
>>>> Am 09/06/2013 04:33 AM, schrieb Johnathan Van Why:
>>>>>
>>>>>
>>>>> We have been benchmarking EtherLab (we're considering switching to it
>>>>> as our robot control system), and have noticed that the Data Logging
>>>>> Service has been dropping data. We created over 100 independent
>>>>> sources in a Simulink model, deployed to EtherLab, and logged all
>>>>> sources at 1 kHz (over 400 KB/s total).
>>>>>
>>>>> After looking at the log data, we noticed that a significant amount of
>>>>> data was dropped. Every 15 minutes, the time variable would jump by 3
>>>>> minutes; the total data we collected was significantly less than we
>>>>> expected for the duration of the run.
>>>>>
>>>>> Is this a known issue? Are we asking too much of the Data Logging
>>>>> Service? Is there anything we can try in order to obtain reliable
>>>>> logging at this data rate?
>>>>>
>>>>> Thank you for any help,
>>>>> Johnathan Van Why
>>>>> Dynamic Robotics Laboratory
>>>>> Oregon State University
>>>>> _______________________________________________
>>>>> etherlab-users mailing list
>>>>> etherlab-users at etherlab.org
>>>>> http://lists.etherlab.org/mailman/listinfo/etherlab-users
>>>>>
>>>>
>>>> Mit freundlichem Gruß
>>>>
>>>> Richard Hacker
>>>>
>>>> --
>>>> ------------------------------------------------------------------------
>>>>
>>>> Richard Hacker M.Sc.
>>>> richard.hacker at igh-essen.com
>>>> Tel.: +49 201 / 36014-16
>>>>
>>>> Ingenieurgemeinschaft IgH
>>>> Gesellschaft für Ingenieurleistungen mbH
>>>> Heinz-Bäcker-Str. 34
>>>> D-45356 Essen
>>>>
>>>> Amtsgericht Essen HRB 11500
>>>> USt-Id.-Nr.: DE 174 626 722
>>>> Geschäftsführung:
>>>> - Dr.-Ing. T. Finke,
>>>> - Dr.-Ing. W. Hagemeister
>>>> Tel.: +49 201 / 360-14-0
>>>> http://www.igh-essen.com
>>>>
>>>> ------------------------------------------------------------------------
>>
>>
>> Mit freundlichem Gruß
>>
>> Richard Hacker
>>
>> --
>> ------------------------------------------------------------------------
>>
>> Richard Hacker M.Sc.
>> richard.hacker at igh-essen.com
>> Tel.: +49 201 / 36014-16
>>
>> Ingenieurgemeinschaft IgH
>> Gesellschaft für Ingenieurleistungen mbH
>> Heinz-Bäcker-Str. 34
>> D-45356 Essen
>>
>> Amtsgericht Essen HRB 11500
>> USt-Id.-Nr.: DE 174 626 722
>> Geschäftsführung:
>> - Dr.-Ing. T. Finke,
>> - Dr.-Ing. W. Hagemeister
>> Tel.: +49 201 / 360-14-0
>> http://www.igh-essen.com
>>
>> ------------------------------------------------------------------------

Mit freundlichem Gruß

Richard Hacker

-- 
------------------------------------------------------------------------

Richard Hacker M.Sc.
richard.hacker at igh-essen.com
Tel.: +49 201 / 36014-16

Ingenieurgemeinschaft IgH
Gesellschaft für Ingenieurleistungen mbH
Heinz-Bäcker-Str. 34
D-45356 Essen

Amtsgericht Essen HRB 11500
USt-Id.-Nr.: DE 174 626 722
Geschäftsführung:
- Dr.-Ing. T. Finke,
- Dr.-Ing. W. Hagemeister
Tel.: +49 201 / 360-14-0
http://www.igh-essen.com

------------------------------------------------------------------------