[etherlab-users] Working counter changed to 0/113

[pier]

Dear Martin

I followed your suggestions


Now we installed kernel 3.2.57-rt83 ( patch rt83 )


Application runs at 1.5 Millisecond

Now Priority  of Ethercat-OP is 99 and application is 80

with FIFO Scheduler


Working counter sometimes is still from  139/139 to 0/139

And with  ethercat debug 1  .... show a couple of dumped frames

it may happen every 20 minutes but it's  occasional...

may not happen for an hour or 2


I saw in your email you use 3.10.x series...

Would it have best performance in this case ?



This command :

*$ NETDEVNAME=eth1*

*>$ ethtool --coalesce $NETDEVNAME adaptive-rx off adaptive-tx off 
rx-usecs 0 rx-frames 0 rx-usecs-irq 0 rx-frames-irq 0 tx-usecs 0 
tx-frames 0 tx-usecs-irq 0 tx-frames-irq 0 pkt-rate-low 0 pkt-rate-high 0
*


gives this output :

*adaptive-rx unmodified, ignoring *

*adaptive-tx unmodified, ignoring *

*pkt-rate-low unmodified, ignoring *

*pkt-rate-high unmodified, ignoring *

*rx-frames unmodified, ignoring *

*rx-usecs-irq unmodified, ignoring *

*rx-frames-irq unmodified, ignoring *

*tx-usecs unmodified, ignoring *

*tx-frames unmodified, ignoring *

*tx-usecs-irq unmodified, ignoring *

*tx-frames-irq unmodified, ignoring *


any other things I can try ?


Thank you very much...


Best Regards

Pier









On 11/04/14 09:32, Martin Troxler wrote:
> Hi Pier,
>
> On 10.04.2014 14:12, pier wrote:
>> What you write works only with the realtime kernel... ?
>>
> No, but you will certainly discover other latency effects.
>> We are using the Standard Ubuntu Kernel
>>
>> The application runs under a Software Interrupt at  1.5 or 2 milliseconds...
>>
>> we measured that it  may have around 100 microseconds variation... ( Do you call it Jitter ? )
> For how long did you run cyclictest and with what cpu/disk load? For tips see
> https://rt.wiki.kernel.org/index.php/RT_PREEMPT_HOWTO
> I am certain that you will get latencies > 10ms sooner or later with a "normal" kernel.
>> So this is ok for our control application....
>>
> Our app runs with 4kHz.
>>
>> I  did not know that the realtime kernel it's a must for etherlab...
> It is not a must. But your realtime task will not run smooth.
>>
>> When sometimes ago I tried to use the Realtime kernel from the Ubuntu Repository
>>
>> the size of the video screen was limited to 1024*768  and we cannot use the 1920*1080
>>
>> screen resolution for the Graphic Application and Video that we have.
>>
>> Also there was another restriction that now I do not recall now....
> We use Ubuntu 12.04 LTS as you do, but with our own kernel (3.6 or 3.10 at the moment) built from sources and it works
> as with the default Ubuntu kernel
>>
>> Do you think that the  : Working counter changed to 0/113
>>
>> ( that may happens once every 2 or 3 hours )
> Ok. That's not very often.
>> it's because we use the standard kernel ?
>>
> Probably.
>> Is the realtime kernel the only solution ?
>>
> I would give it a try.
>>
> Regards
> Martin
>
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