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

[Mike Galbraith]

On Fri, 2006-06-02 at 23:18 +1000, Peter Williams wrote:
> Mike Galbraith wrote:
> > On Fri, 2006-06-02 at 15:55 +1000, Peter Williams wrote:
> >> Chandra Seetharaman wrote:
> >>> On Thu, 2006-06-01 at 14:04 +0530, Balbir Singh wrote:
> >>>> Hi, Kirill,
> >>>>
> >>>> Kirill Korotaev wrote:
> >>>>>> 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?
> >>>>> Sure! You can check OpenVZ project (http://openvz.org) for example of 
> >>>>> required resource management. BTW, I must agree with other people here 
> >>>>> who noticed that per-process resource management is really useless and 
> >>>>> hard to use :(
> >>> I totally agree.
> >> "nice" seems to be doing quite nicely :-)
> >>
> >> To me this capping functionality is a similar functionality to that 
> >> provided by "nice" and all that's needed to make it useful is a command 
> >> (similar to "nice") that runs tasks with caps applied.
> > 
> > Similar in that they are both inherited.  Very dissimilar in that the
> > effect of nice is not altered by fork whereas the effect of a cap is.
> > 
> > Consider make.  A cap on make itself isn't meaningful, and _any_ per
> > task cap you put on it with the intent of managing the aggregate, is
> > defeated by the argument -j.  Per task caps require omniscience to be
> > effective in managing processes.  That's a pretty severe limitation.
> 
> These caps aren't trying to control aggregates but with suitable 
> software they can be used to control aggregates.

How?  How would you deal with the make example with per task caps.

	-Mike

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