`Balbir Singh wrote:> On Fri, Jun 5, 2009 at 11:33 AM, Avi Kivity <avi@redhat.com> wrote:> >> Bharata B Rao wrote:>> >>>> Another way is to place the 8 groups in a container group, and limit>>>>  that to 80%. But that doesn't work if I want to provide guarantees to>>>>  several groups.>>>>>>>> >>> Hmm why not ? Reduce the guarantee of the container group and provide>>> the same to additional groups ?>>>>>> >> This method produces suboptimal results:>>>> \$ cgroup-limits 10 10 0>> [50.0, 50.0, 40.0]>>>> I want to provide two 10% guaranteed groups and one best-effort group.>>  Using the limits method, no group can now use more than 50% of the>> resources.  However, having the first group use 90% of the resources does>> not violate any guarantees, but it not allowed by the solution.>>>> >> How, it works out fine in my calculation>> 50 + 40 for G2 and G3, make sure that G1 gets 10%, since others are> limited to 90%> 50 + 40 for G1 and G3, make sure that G2 gets 10%, since others are> limited to 90%> 50 + 50 for G1 and G2, make sure that G3 gets 0%, since others are> limited to 100%> It's fine in that it satisfies the guarantees, but it is deeply suboptimal.  If I ran a cpu hog in the first group, while the other two were idle, it would be limited to 50% cpu.  On the other hand, if it consumed all 100% cpu it would still satisfy the guarantees (as the other groups are idle).The result is that in such a situation, wall clock time would double even though cpu resources are available.> Now if we really have zeros, I would recommend using>> cgroup-limits 10 10 and you'll see that you'll get 90, 90 as output.>> Adding zeros to the calcuation is not recommended. Does that help?What do you mean, it is not recommended? I have two groups which need at least 10% and one which does not need any guarantee, how do I express it?In any case, changing the zero to 1% does not materially change the results.-- I have a truly marvellous patch that fixes the bug which thissignature is too narrow to contain.`