[ECOS] cyg_scheduler_lock() understanding...

[Stefan Sommerfeld]

Hi,
>>
>> I still search for the delay DSR and found it that the DSR will be
>> permitted due to a scheduler_lock. I quickly have some question while 
>> going
>> deeper into ecos.
>>
>> Does the scheduler_lock also permits the thread switching? Or is it
>> possible that the scheduler switches to another thread while in lock 
>> mode?
>>
>> If thread switching is permitted, how could the scheduler_lock be higher
>> than one if no dsr or isr calls scheduler_lock()?
>
> Actually, every ISR causes a scheduler lock (it's part of the entry
> protocol into the system).  So, if the scheduler was locked for some
> other reason before the ISR happened, it will still be locked when it
> finishes and DSR processing will be postponed until it is freed (i.e.
> the scheduler lock value returns to zero).
>
> You can determine, in great detail, what's happening here by enabling
> the system trace/log features.  This will tell you when the scheduler
> gets locked (and where), when interrupts occur, etc.
>
Aha... i see. So scheduler can only be locked by a thread (one time) and by 
multiple irq's. What i see are sometimes delays above 10ms between lock and 
unlock. Is the unlock_inner() scheduler method save? Or can it be 
interrupted by in irq which then causes the lock counter to change?

My problems appear after a longer time (more then 10 mins), so heavy output 
would not help :). I already run my software with an ecos which includes 
asserts. Everything seem to be fine, but the scheduler_lock load increases. 
I'll do further investigation on the irq load.

Bye...

BTW: I found and fixed the serial 16x5x problem i wrote you about 
yesterday. It was caused by disabling the uart by writing a zero to ier. 
Patch will follow after some more tests. 


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