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Subject: Re: [hwloc-devel] Cgroup resource limits
From: Rayson Ho (raysonlogin_at_[hidden])
Date: 2012-11-02 17:54:54


Ralph,

We added cgroups integration support into Grid Engine a few months
ago, and we ended up implementing routines that write values to
"memory.memsw.limit_in_bytes", "memory.limit_in_bytes",
"memory.soft_limit_in_bytes", etc... We just simply write the values
out to the cgroups files.

http://blogs.scalablelogic.com/2012/05/grid-engine-cgroups-integration.html

I am interested in seeing how Greenplum/EMC implements cgroups limits.

Brice - cgroups allow system administrators to set the resource limit
of a process (or a group of processes) by interacting with the cgroups
virtual fs. Once the processes are added to a cgroup, the memory usage
limit can be added or changed as simply as just just by doing:

# echo 4M > /sys/fs/cgroup/memory/0/memory.limit_in_bytes

For details, see "3. User Interface":
http://www.kernel.org/doc/Documentation/cgroups/memory.txt

Rayson

==================================================
Open Grid Scheduler - The Official Open Source Grid Engine
http://gridscheduler.sourceforge.net/

On Fri, Nov 2, 2012 at 5:18 PM, Brice Goglin <Brice.Goglin_at_[hidden]> wrote:
> Hello Ralph,
>
> I am not very familiar with these features. What system mechanism do you
> currently use for this? Linux cgroups? Any concrete example of what you
> would like to do?
>
> Brice
>
>
>
> Le 02/11/2012 22:12, Ralph Castain a écrit :
>> Hi folks
>>
>> We (Greenplum) have a need to support resource limits (e.g., memory and cpu usage) on processes running under Open MPI's RTE. OMPI uses hwloc for processor and memory affinity, so this seems a likely place to add the required support. Jeff tells me that it doesn't yet exist in hwloc - I'm wondering if you would welcome and/or be willing to consider contributions from our engineers towards adding this capability?
>>
>> Obviously, we'd need to discuss how and where to do the extension. Just wanted to first see if this is an option, or if we should do it directly in OMPI.
>> Ralph
>>
>>
>> _______________________________________________
>> hwloc-devel mailing list
>> hwloc-devel_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/hwloc-devel
>
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