On Jul 10, 2007, at 11:40 AM, Scott Atchley wrote:
On Jul 10, 2007, at 1:14 PM, Christopher D. Maestas wrote:
Has anyone seen the following message with Open MPI:
---
warning:regcache incompatible with malloc
---
<snip>
---
We don't see this message with mpich-mx-1.2.7..4
MX has an internal registration cache that can be enabled with
MX_RCACHE=1 or disabled with MX_RCACHE=0 (the default before MX-1.2.1
was off, and starting with 1.2.1 the default is on). If it is on, MX
checks to see if the application is trying to override malloc() and
other memory handling functions. If so, it prints the error that you
are seeing and fails to use the registration cache.
Open MPI can use the regcache if you set MX_RCACHE=2. This tells MX
to skip the malloc() check and use the cache regardless. In the case
of Open MPI, this is believed to be safe. That will not be true for
all applications.
MPICH-MX does not manage memory, so MX_RCACHE=1 is safe to use unless
the user's application manages memory.
Scott -
I'm having trouble getting the warning to go away with Open MPI.
I've disabled our copy of ptmalloc2, so we're not providing a malloc
anymore. I'm wondering if there's also something with the use of
DSOs to load libmyriexpress? Is your belief that MX_RCACHE=2 is safe
just for the BTL or for the MTL as well?
Brian
--
Brian W. Barrett
Networking Team, CCS-1
Los Alamos National Laboratory
