Re: [RFC 3/5] sched: Add CPU rate hard caps

[Balbir Singh <balbir@in.ibm.com>]

Kirill Korotaev wrote:
>>> Using a timer for releasing tasks from their sinbin sounds like a  bit
>>> of an overhead. Given that there could be 10s of thousands of tasks.
>>
>>
>>
>> The more runnable tasks there are the less likely it is that any of 
>> them is exceeding its hard cap due to normal competition for the 
>> CPUs.  So I think that it's unlikely that there will ever be a very 
>> large number of tasks in the sinbin at the same time.
> 
> for containers this can be untrue... :( actually even for 1000 tasks (I 
> suppose this is the maximum in your case) it can slowdown significantly 
> as well.

Do you have any documented requirements for container resource management?
Is there a minimum list of features and nice to have features for containers
as far as resource management is concerned?


> 
>>> Is it possible to use the scheduler_tick() function take a look at all
>>> deactivated tasks (as efficiently as possible) and activate them when
>>> its time to activate them or just fold the functionality by defining a
>>> time quantum after which everyone is worken up. This time quantum
>>> could be the same as the time over which limits are honoured.
> 
> agree with it.

Thinking a bit more along these lines, it would probably break O(1). But I guess a good
algorithm can amortize the cost.

> 
> Kirill
> 
-- 

	Balbir Singh,
	Linux Technology Center,
	IBM Software Labs