Enabling/disabling Myrinet shared memory with mpiexec

[Patrick Geoffray]

Chris Samuel wrote:
> On Fri, 1 Apr 2005 01:39 pm, Patrick Geoffray wrote:

> So if GMPI_SHMEM_PREFIX isn't set they'll use a sensible default and I don't 
> need to worry about it unless I want to disable it or change to the NUMA 
> variant ?

Yes. The NUMA variant is pretty exotic also (multiple NICs in large 
SMPs), so GMPI_SHMEM is really only used to turn shared memory off by 
setting it to 0.

You can also note that shared memory is automatically turned off if the 
blocking received mode is selected (--gm-recv blocking): with shared 
memory enabled, you need to look for incoming messages from two 
different sources (shared memory and network), so you cannot block on 
one of them.

Patrick
-- 

Patrick Geoffray
Myricom, Inc.
http://www.myri.com