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

[Keir Fraser <keir@xxxxxxxxxxxxx>]

The patch fixes sched-credit vcpu weighting somehow, I guess. How does it do
this?

 -- Keir


On 8/6/07 01:17, "Atsushi SAKAI" <sakaia@xxxxxxxxxxxxxx> wrote:

> 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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