lkml.org 
[lkml]   [2009]   [Jun]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC] CPU hard limits
On Fri, Jun 05, 2009 at 01:53:15AM -0700, Paul Menage wrote:
> On Wed, Jun 3, 2009 at 10:36 PM, Bharata B
> Rao<bharata@linux.vnet.ibm.com> wrote:
> > - Hard limits can be used to provide guarantees.
> >
>
> This claim (and the subsequent long thread it generated on how limits
> can provide guarantees) confused me a bit.
>
> Why do we need limits to provide guarantees when we can already
> provide guarantees via shares?

shares design is proportional and hence it can't by itself provide
guarantees.

>
> Suppose 10 cgroups each want 10% of the machine's CPU. We can just
> give each cgroup an equal share, and they're guaranteed 10% if they
> try to use it; if they don't use it, other cgroups can get access to
> the idle cycles.

Now if 11th group with same shares comes in, then each group will now
get 9% of CPU and that 10% guarantee breaks.

Regards,
Bharata.


\
 
 \ /
  Last update: 2009-06-05 11:31    [W:0.128 / U:0.048 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site