[etherlab-users] schedule_timeout() code issue
Andre Puschmann
andre.puschmann at imms.de
Mon Mar 30 09:57:44 CEST 2009
Hi list,
I already posted this message on the developers list some days ago.
Looks like
there is not much traffic on that one, so I am trying to ask the
question here, too.
Sorry for cross posting.
"I got a question regarding the schedule_timeout(1) functionality used in
master.c in ec_master_idle_thread() and ec_master_operation_thread().
The code calls schedule_timeout(1) which I interpret as "wait for a
message but not longer then 10ms (assuming HZ==100) or 1ms (assuming
HZ==1000)".
I am new to EtherCAT and I am not sure about the desired functionality.
Is it "wait for a very small amount of time" (which explains the 1) or
is it wait for 10ms or 1ms?
I think in either way, defining the timeout with respect to HZ should be
the better idea.
On the other hand, if HZ is set to 1000, one jiffie is relatively short.
I am afraid if it's worth the extra costs of scheduling (i.e. context
switches). In this case, calling a delay function without scheduling
might be the better solution.
What do you think? Maybe I am completely wrong .."
Best regards,
Andre
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