Mailinglist Archive: opensuse-buildservice (119 mails)

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Re: [opensuse-buildservice] Linux scheduler bugs
  • From: Greg Freemyer <greg.freemyer@xxxxxxxxx>
  • Date: Mon, 2 May 2016 12:56:20 -0400
  • Message-id: <CAGpXXZJP6gyih8J_67kfaxy5=RZ4fEQpenEC_Sm+k69_gOaOMw@mail.gmail.com>
On Mon, May 2, 2016 at 11:54 AM, Jan Engelhardt <jengelh@xxxxxxx> wrote:

On Monday 2016-05-02 16:41, Greg Freemyer wrote:

The scheduler bugs seem to affect systems using the NUMA feature of
the scheduler more than those that don't.

lscpu | grep NUMA

provides information about NUMA. Are the servers in the public
instance of OBS using NUMA based hardware. i.e. Do they have more
than one NUMA node?

Theoretical approach: A worker pool is something that is commonly
scaled horizontally rather than vertically, usually because of cost
per work and redundancy feature set. Finding a system with more than
one node is therefore a bit unlikely, and one with more than two is
virtually nonexistent in such a setting.

But, many of the physical machines are running 12 or more VMs. Not
likely small machines.

A few Intel based servers (build21, build24, and build27) currently
are configured to run 16 VMs (per the status monitor display).

PPC machines build67, build91 and build92 also have 16 VMs configured.

I would not at all be surprised if those 6 machines had a NUMA architecture.

Practical approach: Run a build job with lscpu in it, and find out.
(Though, virtualization may mask the real value and always yield 1.)

I'm assuming the virtualization would indeed mask the real value.
Someone with SSH access to the physical machines would need to run the
command "lscpu | grep NUMA".

Greg
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