[etherlab-users] example code
shabbyx at gmail.com
Wed Nov 20 18:37:38 CET 2013
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
> 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.
> 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
>> 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.
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