Re: [ckrm-tech] [PATCH 0/4] sched: Add CPU rate caps

[Chris Friesen]

Peter Williams wrote:
> These patches implement CPU usage rate limits for tasks.

Personally, I'm more comfortable with guarantees rather than limits.

Specifying a limit doesn't do anything to ensure that a task (or group 
of tasks) gets enough cpu time to actually accomplish anything unless 
you specify limits on every task in the system.

Suppose you have a server app that needs at least 50% of the cpu.  With 
a guarantee, you can say "this guy needs 50%, and I don't care about 
anything else".  With limits you have to flip it around--"all these guys 
together are limited to 50%, and that guy isn't limited".  Seems 
counterintuitive.

Chris


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