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RE: [Xen-devel] Credit scheduler anamoly


  • To: "Atsushi SAKAI" <sakaia@xxxxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
  • From: "Padala, Pradeep" <pradeep.padala@xxxxxx>
  • Date: Tue, 21 Nov 2006 21:19:51 -0600
  • Delivery-date: Tue, 21 Nov 2006 19:19:50 -0800
  • List-id: Xen developer discussion <xen-devel.lists.xensource.com>
  • Thread-index: AccN4+FdmpnVjMg6SD2txy8cjzr1xwAACQ9A
  • Thread-topic: [Xen-devel] Credit scheduler anamoly

> The cap effects for avarage not one time.
> Please send xentop -b (batch) log file.

What do you mean by average ? I am actually measuring the CPU times
every 10 secs in my program. I believe Xentop averages it over 3 secs.
Isn't that long enough time to cap correctly ?

A copy of xentop -b is at http://www.eecs.umich.edu/~ppadala/out.
I set the caps to 4% and 96% and in the first VM, I ran a CPU eater
which is basically 

do {;} {while(1)}

I can run it for a longer period if you want.

Pradeep
 
> >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
> >
> >_______________________________________________
> >Xen-devel mailing list
> >Xen-devel@xxxxxxxxxxxxxxxxxxx
> >http://lists.xensource.com/xen-devel
> >
> 
> 
> 
> 
> 
> 
> 

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