[Mauiusers] detecting and scheduling vmem
roy.dragseth at cc.uit.no
Tue Feb 24 03:37:41 MST 2009
On Friday 20 February 2009 07:08:42 Gareth.Williams at csiro.au wrote:
> Hi All,
> I have been working with CR to get a patch in maui and moab to improve
> treatment of vmem. The patch is in maui-3.2.6p21-snap.1234905291 and will
> be in upcoming moab releases. Many thanks to Brian Christiansen at CR.
> With the patch, maui/moab correctly detects a node's available vmem as
> being the total physical memory plus swap space. This can then be
> scheduled/allocated by requesting vmem and job's virtual memory allocation
> can be limited on a per process basis and periodically measured (and action
> taken or overuse) on a per job basis.
> I think this makes scheduling on vmem a good option. It's a more
> predictable quantity than mem/pmem.
This is great, but is it possible to get
TotMem = (int)(TotMem * MSched.NodeMemOverCommitFactor);
at line 6384? This will make the NODEMEMOVERCOMMITFACTOR work both for mem
and swap as earlier.
We want to use a slight overcommit to allow a user to specify -lpvmem=2gb
instead of -lpvmem=2000mb on a machine with 2GB RAM per core. Some of the ram
isn't available to userspace, so using 2gb will underutilize the cores on a
node and users aren't really good at guessing the memory consumption anyway.
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