Re: [Xen-devel] [PATCH][RFC] consider weight for vcpu-pin case

[Atsushi SAKAI <sakaia@xxxxxxxxxxxxxx>]

Hi, Keir

  Would you give me a comment on this?

Thanks
Atsushi SAKAI


Atsushi SAKAI <sakaia@xxxxxxxxxxxxxx> wrote:

> Hi, 
> 
> This patch intends to consider weight for vcpu-pin case.
> (in other words, pcpu.credit > 30msec case.) 
> In this case, weight parameter does not work appropriately.
> By applying this patch, weight parameter works.
> 
> This patch consists 3-parts
> 1)Weight Calculation for vcpupin
>   csched_consider_vcpupin()  (add)
> 
> 2)Credit Balance Calculation for vcpupin  
>   csched_consider_vcpupin_credit_balance()  (add)
> 
> 3)Other credit correction factor calculation.
>   csched_acct()  (modified like variable csched_corr_factor)
> 
> For test
> If you want to test this patch, please test like following configuration
> at 4pcpu machine.
> Dom1 vcpu0.0-1 vcpu1.0-1 weight 256
> Dom2 vcpu0.0-1 vcpu1.0-1 weight 512
> N.B.)0-1 means pininfo(xm vcpu-pin)
> If this patch does not applied, xentop shows each cpu 100%.
> But If you use this patch, xentop shows 66%, 133% for each domain.
> 
> Discussion Points
> 1) many loop is permitted?
> 2) arithmetic divide is still remain 4 points for each vcpu.
> 3) Is it enough tuned?(Need more tune) 
> 
> 
> Any comments will be appreciated.
> 
> c.f 
> this problem is already questioned six month ago.
> http://lists.xensource.com/archives/html/xen-devel/2006-10/msg00365.html
> At this moment, I think this effect is very low.
> But a month ago, somebody suggested me this issue is important.
> (SMP like boot 8cpu with 2domain in 1pcpu share, weight does not effect.
> This also effects NUMA system weight.)
>  
> Thanks
> Atsushi SAKAI



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