| Re: [ckrm-tech] [patch00/05]: Containers(V2)- Introduction [message #6665] |
Thu, 21 September 2006 01:45  |
Chandra Seetharaman
Messages: 88
Registered: August 2006
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Member |
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On Wed, 2006-09-20 at 17:42 -0700, Paul Menage wrote:
> On 9/20/06, Paul Jackson <pj@sgi.com> wrote:
> > Chandra wrote:
> > > AFAICS, That doesn't help me in over committing resources.
> >
> > I agree - I don't think cpusets plus fake numa ... handles over commit.
> > You might could hack up a cheap substitute, but it wouldn't do the job.
>
> I have some patches locally that basically let you give out a small
> set of nodes initially to a cpuset, and if memory pressure in
> try_to_free_pages() passes a specified threshold, automatically
> allocate one of the parent cpuset's unused memory nodes to the child
> cpuset, up to specified limit. It's a bit ugly, but lets you trade of
> performance vs memory footprint on a per-job basis (when combined with
> fake numa to give lots of small nodes).
Interesting. So you could set up the fake node with "guarantee" and let
it grow till "limit" ?
BTW, can you do these with fake nodes:
- dynamic creation
- dynamic removal
- dynamic change of size
Also, How could we account when a process moves from one node to
another ?
>
> Paul
--
------------------------------------------------------------ ----------
Chandra Seetharaman | Be careful what you choose....
- sekharan@us.ibm.com | .......you may get it.
------------------------------------------------------------ ----------
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| Re: [ckrm-tech] [patch00/05]: Containers(V2)- Introduction [message #6749 is a reply to message #6665] |
Thu, 21 September 2006 01:52  |
Paul Menage
Messages: 642
Registered: September 2006
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Senior Member |
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On 9/20/06, Chandra Seetharaman <sekharan@us.ibm.com> wrote:
>
> Interesting. So you could set up the fake node with "guarantee" and let
> it grow till "limit" ?
Sure - that works great. (Theoretically you could do this all in
userspace - start by assigning "guarantee" nodes to a
container/cpuset and when it gets close to its memory limit assign
more nodes to it. But in practice userspace can't keep up with rapid
memory allocators.
>
> BTW, can you do these with fake nodes:
> - dynamic creation
> - dynamic removal
> - dynamic change of size
The current fake numa support requires you to choose your node layout
at boot time - I've been working with 64 fake nodes of 128M each,
which gives a reasonable granularity for dividing a machine between
multiple different sized jobs.
>
> Also, How could we account when a process moves from one node to
> another ?
If you want to do that (the systems I'm working on don't really) you
could probably do it with the migrate_pages() syscall. It might not be
that efficient though.
Paul
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