Re: [Xen-devel] credit vs sedf scheduler

["Liang Yang" <yangliang_mr@xxxxxxxxxxx>]

Hi Emmanuel,

Do you mean, if the number of VCPUs is equal to the number of physcial CPUs, 
Xen will still call credit scheduler to allocate CPU resources amongst V 
CPUs even though each guest domain is assigned a fixed VCPU/CPU using xm 
vcpu-pin?
The purpose I assign each domain a CPU and fix the mapping of VCPU to CPU is 
I want each guest domain get equal CPU resources at any time. I don't want 
to credit scheduler get involved.
Regards,

Liang

----- Original Message ----- 
From: "Emmanuel Ackaouy" <ack@xxxxxxxxxxxxx>
To: "Liang Yang" <multisyncfe991@xxxxxxxxxxx>
Cc: "xen-devel" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Sent: Thursday, November 16, 2006 9:37 AM
Subject: Re: [Xen-devel] credit vs sedf scheduler


> On Thu, Nov 16, 2006 at 09:29:30AM -0700, Liang Yang wrote:
> >    Hi,
> >
> >    Can I used vcpu-pin to avoid CPU scheduler overhead? Suppose I have 
> > four
> >    CPUs, if I used xm vcpu-pin to fix the mapping of each physcial CPU to
> >    virtual CPU. So credit scheduler will not be needed.
> >
> >    Liang
> Pinning all your VCPUs will not stop Xen from executing various
> scheduler code paths.
>
> Why are you worried about the scheduler overhead? It should be
> negligeable.
>
> Emmanuel.

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