OK, I see the following in the documentation:
When you get this error:
RTAPI: ERROR: Unexpected realtime delay on task n
This error is generated by rtapi based on an indication from RTAI that a
deadline was missed. It is usually an indication that the BASE_PERIOD in
the [EMCMOT] section of the ini file is set too low. You should run the
Latency Test for an extended period of time to see if you have any
delays that would cause this problem. If you used the Stepconf Wizard,
run it again, and test the Base Period Jitter again, and adjust the Base
Period Maximum Jitter on the Basic Machine Information page. You might
have to leave the test running for an extended period of time to find
out if some hardware causes intermittent problems.
LinuxCNC tracks the number of CPU cycles between invocations of the
real-time thread. If some element of your hardware is causing delays or
your realtime threads are set too fast you will get this error.
Note
This error is only displayed once per session. If you had your
BASE_PERIOD too low you could get hundreds of thousands of error
messages per second if more than one was displayed.
So I need to either increase the base period or do something to lower my
jitter.
I will work on it and see what happens.
Any other advise would be welcome.
Thanks,
Jim
On 5/6/2016 11:27 AM, Jim Craig wrote:
> Jon,
>
> I did mean us, not ms. I sent another message to try and clear the muddy
> waters on that one.
>
> So what is the jitter limit at which the realtime error is thrown? Is
> this something that can be changed in the configuration somewhere?
>
> I have been under the impression that 25us is acceptable for stepping as
> long as you can generate the speed you need within the acceptable
> limits. Many have claimed that you need very low jitter values and
> others have claimed that it is not as critical as some make it seem.
>
> I did notice that nothing was changing in the halfile when I would
> change the jitter value in stepconf. I was curious if this was changing
> anything except the theoretical maximum pulse rate and therefore the
> theoretical maximum velocity.
>
> Thanks,
>
> Jim
>
>
>
> On 5/6/2016 11:06 AM, Jon Elson wrote:
>> On 05/06/2016 09:12 AM, Jim Craig wrote:
>>> I have set up my router with my new computer. This computer runs at
>>> about 25ms jitter on the base thread for hours with 2 glxgears running,
>>> moving windows, copying files etc.
>> I hope that is 25 us, not ms. 25 us is not great, as it
>> causes a 2.5% fluctuation in the sampling period.
>>> This system runs off a parport, and I set initially set it up in
>>> stepconf wizard to have a 30ms jitter value.
>>>
>>> When I run LinuxCNC I get a realtime error a few minutes after I start
>>> the program.
>> The realtime error message tells the magnitude of the error,
>> that is important. If it doesn't exceed your 25 us jitter,
>> that is not a disaster. But, the realtime error message
>> only fires once per run of LinuxCNC, and so you are then
>> blind to any more serious errors that happen later. Not a
>> great situation.
>>> I am using 2.7.4. This is repeatable and happens each and
>>> every time I run LinuxCNC.
>> Yes, you will only get the message once. That does NOT mean
>> that the error in not happening again!
>>> I reran stepconf and changed the jitter value to 50ms to see if that
>>> would fix it and it did not change anything.
>>>
>>>
>> Stepconf has NOTHING to do with anything except software
>> stepping, so it certainly will not "fix" this problem.
>> What you did will generate a more conservative software
>> stepping configs file set.
>>
>> Jon
>>
>> ------------------------------------------------------------------------------
>> Find and fix application performance issues faster with Applications Manager
>> Applications Manager provides deep performance insights into multiple tiers
>> of
>> your business applications. It resolves application problems quickly and
>> reduces your MTTR. Get your free trial!
>> https://ad.doubleclick.net/ddm/clk/302982198;130105516;z
>> _______________________________________________
>> Emc-users mailing list
>> [email protected]
>> https://lists.sourceforge.net/lists/listinfo/emc-users
>>
>
> ------------------------------------------------------------------------------
> Find and fix application performance issues faster with Applications Manager
> Applications Manager provides deep performance insights into multiple tiers of
> your business applications. It resolves application problems quickly and
> reduces your MTTR. Get your free trial!
> https://ad.doubleclick.net/ddm/clk/302982198;130105516;z
> _______________________________________________
> Emc-users mailing list
> [email protected]
> https://lists.sourceforge.net/lists/listinfo/emc-users
>
------------------------------------------------------------------------------
Find and fix application performance issues faster with Applications Manager
Applications Manager provides deep performance insights into multiple tiers of
your business applications. It resolves application problems quickly and
reduces your MTTR. Get your free trial!
https://ad.doubleclick.net/ddm/clk/302982198;130105516;z
_______________________________________________
Emc-users mailing list
[email protected]
https://lists.sourceforge.net/lists/listinfo/emc-users
