[ovirt-users] Huge pages in guest with newer oVirt versions

[Arik Hadas]

On Mon, Sep 18, 2017 at 10:50 PM, Martin Polednik <mpoledni at redhat.com>
wrote:

> The hugepages are no longer a hook, but part of the code base. They

can be configured via engine property `hugepages`, where the value of
> property is size of the pages in KiB (1048576 = 1G, 2048 = 2M).
>

Note that the question is about 4.1 and it doesn't seem like this change
was backported to the 4.1 branch, right?


> Specifying any other size not supported by the architecture (or just
> "1") will use platform's default hugepage size.
>

I wonder if the end-to-end scenario, i.e., using the engine, of this ever
worked.
This feature is broken on the master branch because of the switch to engine
xml and is supposed to be fixed by [1]. However, while testing that fix I
noticed that a check done by the scheduler [2] actually prevents us from
setting a value that is not supported by the host.
Is this part really important?

[1] https://gerrit.ovirt.org/#/c/81860/
[2]
https://github.com/oVirt/ovirt-engine/blob/master/backend/manager/modules/bll/src/main/java/org/ovirt/engine/core/bll/scheduling/policyunits/HugePagesFilterPolicyUnit.java#L56


>
> On Mon, Sep 18, 2017 at 11:39 AM, Gianluca Cecchi
> <gianluca.cecchi at gmail.com> wrote:
> > Hello,
> > I would like to go again in deep with what preliminary tested and already
> > discussed here:
> >
> > http://lists.ovirt.org/pipermail/users/2017-April/081320.html
> >
> > I'm testing an oVirt node in 4.1.6-pre
> >
> > I don't find the vdsm hook for huge pages; doing a search I get these:
> >
> > vdsm-hook-ethtool-options.noarch : Allow setting custom ethtool options
> for
> > vdsm controlled nics
> > vdsm-hook-fcoe.noarch : Hook to enable FCoE support
> > vdsm-hook-openstacknet.noarch : OpenStack Network vNICs support for VDSM
> > vdsm-hook-vfio-mdev.noarch : Hook to enable mdev-capable devices.
> > vdsm-hook-vhostmd.noarch : VDSM hook set for interaction with vhostmd
> > vdsm-hook-vmfex-dev.noarch : VM-FEX vNIC support for VDSM
> >
> > Did anything change between 4.1.1 and 4.1.5/4.1.6?
> >
> > I'm making preliminary tests with an Oracle RDBMS and HammerDB in both a
> > physical server and a "big" VM inside another same hw server configured
> with
> > oVirt.
> >
> > Results are not bad, but I would like to see having huge pages inside the
> > guest how could change results.
> >
> > Just for reference:
> >
> > The 2 Physical server are blades with each one:
> > 2 sockets, each one with 14 cores and ht enabled, so in total 56
> > computational threads
> > 256Gb ram
> > huge pages enabled
> >
> > VM configured with this virtual hw on one of them:
> > 2 sockets, each one with 6 cores and ht so in total 24 computational
> threads
> > 64Gb ram
> > no huge pages at the moment
> >
> > Oracle SGA is 32Gb on both physical rdbms and virtual one.
> >
> > Thanks for any insight to test huge pages in guest
> >
> > Gianluca
> >
> > _______________________________________________
> > Users mailing list
> > Users at ovirt.org
> > http://lists.ovirt.org/mailman/listinfo/users
> >
> _______________________________________________
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>
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