[Xen-devel] Credit scheduler anamoly

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Subject:	[Xen-devel] Credit scheduler anamoly
From:	"Padala, Pradeep" <pradeep.padala@xxxxxx>
Date:	Tue, 21 Nov 2006 16:07:00 -0600
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Thread-topic:	Credit scheduler anamoly

I sent the following mail without subscribing to the list, and I am not
sure whether the list accepts mails from non-members. I just subscribed
and re-sending the mail. I apologize if you receive multiple copies.

Hi,

I am using the credit scheduler in the xen-unstable trunk and I am
trying to set a cap on the container CPU entitlement. I have two VMs and
two CPUs. The two VMs are restricted to one CPU using the command xm
vcpu-pin. Now, I want to cap the container CPU consumption say to 4% and
26% of the ONE CPU.

So, I use the following commands.

xm sched-credit -d 73 -c 4
xm sched-credit -d 74 -c 26

When I run Xentop, I see this

apache.padalap.1 ------         83    7.0 ...
apache.padalap.2 -----r        154   25.5 ...

How is this possible when I cap the first VM to 4% ? Am I missing some
thing ? Does credit scheduler fail to enforce small caps ? Note that I
haven't changed the weights and they are set to default 256 each.

Thanks,
Pradeep

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