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Hi Sean,

I can confirm that using only hw:mem_page_size=large on used flavor is
working  with 2MB hugepage.

Anyway, I'm still curious about how Nova selects the hugepage size there is
2MB and 1GB hugepage on the hypervisor and I only put
hw:mem_page_size=large on used flavor. Maybe you can explain more about
this.

Best regards.

On Mon, Feb 13, 2023, 9:27 PM Sean Mooney <smooney at redhat.com> wrote:

> On Mon, 2023-02-13 at 21:21 +0700, Lazuardi Nasution wrote:
> > Hi Sean,
> >
> > Thank you for your explanation. I want to use the 2MB hugepage. So, do
> you
> > mean that I have to put hw:mem_page_size=large on used flavor and
> > hw_mem_page_size=2MB used image? What is the difference with current
> > hw:mem_page_size=2MB on used flavor only?
>
> in general we recomend agains using explict page size unless required
> after extensive performance testing
>
> so generally i would just suggest using hw:mem_page_size=large in the
> flaovr.
>
> if you need to use exiplcit page size for a specifc VNF we advise that you
> set hw_mem_page_size=2MB
> on the image.
>
> That way if you hae 1 flavor with hw:mem_page_size=large and 3 images one
> with hw_mem_page_size=2MB
> another with hw_mem_page_size=1G and a third with hw_mem_page_size not set
> all 3 images can use the same
> flavor.
>
> you should prefer to keep the flaovrs generic by using
> hw_mem_page_size=large|small|any and only set explict page
> zises in the images that need that granularity.
>
> you can set explcit pages sizes in the flavor too but it leasds to a
> combinitorial flavor explostion and is gernerally
> required. in 90% of cases hw:mem_page_size=large in the flavor is all that
> is requried.
> >
> > Best regards.
> >
> > On Mon, Feb 13, 2023 at 8:45 PM Sean Mooney <smooney at redhat.com> wrote:
> >
> > > On Mon, 2023-02-13 at 18:22 +0700, Lazuardi Nasution wrote:
> > > > Hi,
> > > >
> > > > There is a weird situation if it is not a bug.
> > > >
> > > Its not a bug
> > >
> > > hw_mem_page_size can be used in the image only if
> > > hw:mem_page_size=larage or  hw:mem_page_size=any
> > >
> > > in the case of  hw:mem_page_size=large the image can be used to choose
> a
> > > speccific hugepage size
> > >
> > > hw:mem_page_size=large  hw_mem_page_size=1G
> > >
> > > hw:mem_page_size=any will by default be the same as
> hw:mem_page_size=small
> > > and use the smallest pagezise
> > > which is typically 4k. the differnece bettwen hw:mem_page_size=any and
> > > hw:mem_page_size=small is
> > > hw:mem_page_size=any allows the image to set any value for
> > > hw_mem_page_size.
> > > so
> > > hw:mem_page_size=any and hw_mem_page_size=large is valid where as
> > > hw:mem_page_size=small and hw_mem_page_size=large is not and will
> raise an
> > > error.
> > >
> > > when hugepage support was added it was decided that permission form the
> > > operator was required
> > > to allow you to request hugepages via the image which is why the flavor
> > > must have and hw_mem_page_size=large|any
> > > set.
> > >
> > > >  Hugepage instance launching
> > > > is working if I put hw:mem_page_size on the used flavor. But, when I
> try
> > > > the same launching configuration and change hw:mem_page_size on used
> > > flavor
> > > > to hw_mem_page_size on used image, it cannot work as expected. It
> seems
> > > > that this issue is like on
> > > > https://bugzilla.redhat.com/show_bug.cgi?id=1791132, but it still
> > > happens
> > > > on Zed. Is this an old bug? Should I submit a bug report for this?
> > > no we cloased https://bugzilla.redhat.com/show_bug.cgi?id=1791132 as
> not
> > > a bug because they were not aware of this requriement.
> > > >
> > > > Best regards.
> > >
> > >
>
>
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