On Sep 23, 2005, at 1:16 PM, Craig Lam wrote:
> I am writing a soft real time application for use on a cluster whose
> MPI traffic goes over a secure network. (In a locked rack, only I have
> the password to any machine on the network) Since it is soft real
> time, I'd like to take advantage of Linux's SCHED_RR capabilities, but
> the kernel won't let me do this unless I execute as root. Currently
> I've compiling my kernel to allow any user to execute a SCHED_RR task,
> although this is unacceptable and hackish. Is there a simple way to
> allow lam to let root to run MPI programs? #defining
> LAM_ALLOW_RUN_AS_ROOT in ../lam- 7.1.1/share/include/lam_config.h.in
> and lam_config.h doesn't seem to do the trick. Any help is
> appreciated.
Can you expand on that?
The "ALLOW_RUN_AS_ROOT" is a hidden feature that has no analogue in
./configure -- you need to hand-edit the lam_config.h file to set it to
1 before running "make" (we intentionally made it difficult to
discourage this behavior ;-) ). After that, the LAM executables should
simply disable their getuid() checks and allow you to run as root.
--
{+} Jeff Squyres
{+} The Open MPI Project
{+} http://www.open-mpi.org/
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