cvs commit: src/sys/kern kern_sig.c

[David Xu]

David Schultz wrote:

>On Thu, Mar 03, 2005, Mike Silbersack wrote:
>  
>
>>On Thu, 3 Mar 2005, David Schultz wrote:
>>
>>    
>>
>>>Of course, there's another possible solution which is to remove
>>>the swapping code entirely.  That would certainly simplify things,
>>>but it would also make FreeBSD degrade less gracefully under load.
>>>      
>>>
>>I don't think that would be a big loss; by the time you're doing a lot of 
>>process swapping, you're pretty screwed.
>>
>>A process has to be swapped back in in order for it to be killed, right? 
>>We might be better off without swapping, in that case.
>>    
>>
>
>Yeah, with 16K kernel stacks, you'd have to swap a lot of threads
>to make a big difference in the amount of wired memory in the
>system.  KSE helps with this, because processes with thousands of
>user threads don't have thousands of kernel threads.
>
>  
>
This only happens at comparative idle time, if the process is a heavy  
I/O bound process,
this does not help.

>Another thing that swapping does, though, is prevent some
>processes from running for a while when the system is under load,
>thereby reducing contention for resources and allowing the other
>processes to get things done.  If people decide to go this way, it
>might be a good idea to keep the second feature.  It costs very
>little in terms of complexity because no actual swapping is done.
>But who knows?  Maybe nobody cares about this, either...
>
>  
>
I would like to not swap out kernel stack, it allows me to write some 
speedy code,
this is my personal favorit. :=)