[etherlab-users] example code

[Shahbaz Youssefi]

I just sent the patch (the thread title would be different). The patch
provides a function that can be polled to know if the domains have been
received. You can then simply sleep until it becomes true.

Interesting quotes from a certain developer by the way (who was strictly
against this harmless additional functionality):

>  For me, there is no point of busily waiting till your packet arrives,
instead of being relaxed and receiving the packet next cycle.

and in the same email:

> The drawback is that your propagation time from input change to output
reaction is* 2 cycles*, instead of only 1.

and again in the same email:

> I do not think that you have a problem. Draw your operations on a time
line and convince yourself that once you are in in the loop, you have* max
1 cycle* delay from input to output.


On Wed, Nov 20, 2013 at 6:18 PM, Ian Prochazka <jprochazka at persimmontech.com
> wrote:

> Yes, I would also be extremely interested in the patch.
> It would actually be very(!!!) useful to have available variation of
> ecrt_master_receive() that would block and wait till the transaction is
> done and then returns ASAP when it can.
> The other option would be some notification from master or NIC that it
> received and so ecrt_master_receive() call is safe now.
>
> Thanks,
> Ian
>
>
>
> On 11/20/2013 11:39, Jeroen Van den Keybus wrote:
>
>>       Someone actually did that and I extensively tested it. The patch
>>     was very simple.
>>
>>
>> How was this packet arrival time measured ?
>>
>>     ...the ethercat master developers said you don't need to know when a
>>     packet arrives.
>>
>>
>> I could understand their point if the patch would hurt performance too
>> much.
>>
>>     I still have the patch although it needs a bit of adaptation, in
>>     case they come to their senses. Perhaps if others also mention it
>>     would be useful they would accept that function.
>>
>> Well, if it's not too much asked, I'd like to see it.
>>
>> Thanks,
>>
>>
>> J.
>>
>>
>
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