4BSD process starvation during I/O

[David Xu]

Kris Kennaway wrote:

>On Thu, Nov 24, 2005 at 07:52:30AM +0800, David Xu wrote:
>  
>
>>Kris Kennaway wrote:
>>
>>    
>>
>>>Perhaps this can be tweaked.
>>>
>>>Kris
>>>
>>>P.S. Please, no responses about how maybe someone could write a new
>>>scheduler that doesn't have this property.
>>>
>>>
>>>
>>>
>>>      
>>>
>>Can you try it again with FULL_PREEMPTION is turned on ?
>>    
>>
>
>OK.  Is this option believed to be "safe" (i.e. largely free from
>bugs), and would it be useful to test more widely?
>
>Kris
>
>  
>
I didn't test it on big machine. if I remembered it correctly, we only
do preemption at user boundary if the FULL_PREEMPTION is turned off,
you know system thread won't go to user boundary. :-)

David Xu