Re: [Xen-users] ntpd under Xen Dom0 exhibits extremely high jitter/noise? runs stable/quiet under non-xen kernel.

[mail ignored <0.bugs.only.0@xxxxxxxxx>]

hi

On Tue, Jan 12, 2010 at 11:13 PM, Pasi Kärkkäinen <pasik@xxxxxx> wrote:
> How many vcpus does your dom0 have?

4, atm,

xm vcpu-list Domain-0
 Name                                ID  VCPU   CPU State   Time(s) CPU Affinity
 Domain-0                             0     0     0   r--     273.0 any cpu
 Domain-0                             0     1     1   -b-     202.4 any cpu
 Domain-0                             0     2     3   -b-     179.1 any cpu
 Domain-0                             0     3     2   -b-     199.9 any cpu

> Have you configured domain weights (ie. guaranteed cpu time for dom0?)

no, i didn't realize that was available.  how is that explicitly done?
 is that done using the CreditScheduler?

> Have you tried dedicating a single cpu core only for dom0?

no, not yet.  clearly, i could set maxcpus=1 @ grub.  would i also
need to pin the Dom0 cpu to a specific cpu, shomehow?

On Tue, Jan 12, 2010 at 11:37 PM, Fajar A. Nugraha <fajar@xxxxxxxxx> wrote:
> which kernel is it? vanilla? distro-provided? gentoo-xen kernel?

it's distro-provided -- opensuse 11.2's,

 uname -a
  Linux test 2.6.31.8-0.1-xen #1 SMP 2009-12-15 23:55:40 +0100 x86_64
x86_64 x86_64 GNU/Linux

 lsb_release -a
  LSB Version:
core-2.0-noarch:core-3.2-noarch:core-4.0-noarch:core-2.0-x86_64:core-3.2-x86_64:core-4.0-x86_64:desktop-4.0-amd64:desktop-4.0-noarch:graphics-2.0-amd64:graphics-2.0-noarch:graphics-3.2-amd64:graphics-3.2-noarch:graphics-4.0-amd64:graphics-4.0-noarch
  Distributor ID: SUSE LINUX
  Description:    openSUSE 11.2 (x86_64)
  Release:        11.2
  Codename:       n/a

 rpm -qa | grep -i ^xen-3
  xen-3.4.1_19718_04-28.1.x86_64

> FWIW, a quick workaround is to use kernel 2.6.18. I've been using
> RHEL's kernel-xen (2.6.18-164.2.1.el5xen) and it works great WRT
> time/ntp.

good to know. although @downstream, they're unable to reproduce this
problem, i'm able to on, as above, 5 different mobos from 3 different
vendors.

commonalities are (1) opensuse 11.2, (2) similar install profiles, (3)
AMD Deneb cores (Phenom II X4s)

whether this is an issue due to my local environmentS, opensuse or
xen, i'd like to find/fix it.

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