Which kernel version did you say they're running? Did you try running with "nohz=off"?

On Wed, Apr 11, 2012 at 5:00 PM, Gilbert E. Detillieux <gedetil@cs.umanitoba.ca> wrote:
Howdy folks!

I asked this at last night's meeting, as my "stumper of the month", but didn't get any solutions or leads.  So, I thought I'd ask again here...

After upgrading many of our systems, both workstations and servers, from CentOS 5.x to Scientific Linux 6.x, I'm seeing higher load averages on idle systems than I used to.  Under EL5, loads would drop to zero and pretty much stay there most of the time for idles systems.  Under EL6, the load might drop down to 0.1, but doesn't stay there for very long, and even on seemingly idle systems, I see loads at or near 1 (sometimes even higher than 1 on some of our servers).  It's also intermittent, with load averages dropping and climbing on fairly short intervals (of a few minutes or so).

Running top, iotop, ftop, iftop, etc. doesn't really point to any major culprits.  I've even run PowerTop, and implemented some of its suggested improvements, but that didn't make a difference on load.

Just wondering if anyone else has seen similar behaviour with hosts running Red Hat and/or Fedora distributions?  Would moving to the "tickless" kernel have anything to do with it?  (I.e. does it somehow affect the way load averages are calculated?)

Or is it some system service that can be shut down?  (If it is, it's not creating an obvious load on its own, that top or ftop would show, but it may be affecting something in the kernel...)

Any suggestions?

--
Gilbert E. Detillieux           E-mail: <gedetil@muug.mb.ca>
Manitoba UNIX User Group        Web:    http://www.muug.mb.ca/
PO Box 130 St-Boniface          Phone:  (204)474-8161
Winnipeg MB CANADA  R2H 3B4     Fax:    (204)474-7609
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