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Subject: Re: [OMPI users] Error in Binding MPI Process to a socket
From: Terry Dontje (terry.dontje_at_[hidden])
Date: 2011-03-18 06:29:46


On 03/17/2011 03:31 PM, vaibhav dutt wrote:
> Hi,
>
> Thanks for your reply. I tried to execute first a process by using
>
> mpirun -machinefile hostfile.txt --slot-list 0:1 -np 1
>
> but it gives the same as error as mentioned previously.
>
> Then, I created a rankfile with contents"
>
> rank 0=t1.tools.xxx slot=0:0
> rank 1=t1.tools.xxx slot=1:0.
>
> and the used command
>
> mpirun -machinefile hostfile.txt --rankfile my_rankfile.txt -np 2
>
> but ended up getting same error. Is there any patch that I can
> install in my system to make it
> topology aware?
>
You may want to check that you have numa turned on.

If you look in your /etc/grub.conf file does the kernel line have
"numa=on" in it. If not I would suggest making a new boot line and
appending numa=on at the end. That way if the new boot line doesn't
work you'll be able to go back to the old one. Anyway, my boot line
that turns on numa looks like the following:

title Red Hat Enterprise Linux AS-up (2.6.9-67.EL)
     root (hd0,0)
     kernel /vmlinuz-2.6.9-67.EL ro root=LABEL=/ console=tty0
console=ttyS0,9600 rhgb quiet numa=on

And of course once you've saved the changes you'll need to reboot and
select the new boot line at the grub menu.

--td

> Thanks
>
>
> On Thu, Mar 17, 2011 at 2:05 PM, Ralph Castain <rhc_at_[hidden]
> <mailto:rhc_at_[hidden]>> wrote:
>
> The error is telling you that your OS doesn't support queries
> telling us what cores are on which sockets, so we can't perform a
> "bind to socket" operation. You can probably still "bind to core",
> so if you know what cores are in which sockets, then you could use
> the rank_file mapper to assign processes to groups of cores in a
> socket.
>
> It's just that we can't do it automatically because the OS won't
> give us the required info.
>
> See "mpirun -h" for more info on slot lists.
>
> On Mar 17, 2011, at 11:26 AM, vaibhav dutt wrote:
>
> > Hi,
> >
> > I am trying to perform an experiment in which I can spawn 2 MPI
> processes, one on each socket in a 4 core node
> > having 2 dual cores. I used the option "bind to socket" which
> mpirun for that but I am getting an error like:
> >
> > An attempt was made to bind a process to a specific hardware
> topology
> > mapping (e.g., binding to a socket) but the operating system
> does not
> > support such topology-aware actions. Talk to your local system
> > administrator to find out if your system can support topology-aware
> > functionality (e.g., Linux Kernels newer than v2.6.18).
> >
> > Systems that do not support processor topology-aware
> functionality cannot
> > use "bind to socket" and other related functionality.
> >
> >
> > Can anybody please tell me what is this error about. Is there
> any other option than "bind to socket"
> > that I can use.
> >
> > Thanks.
> > _______________________________________________
> > users mailing list
> > users_at_[hidden] <mailto:users_at_[hidden]>
> > http://www.open-mpi.org/mailman/listinfo.cgi/users
>
>
> _______________________________________________
> users mailing list
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>
>
>
> _______________________________________________
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-- 
Oracle
Terry D. Dontje | Principal Software Engineer
Developer Tools Engineering | +1.781.442.2631
Oracle *- Performance Technologies*
95 Network Drive, Burlington, MA 01803
Email terry.dontje_at_[hidden] <mailto:terry.dontje_at_[hidden]>



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