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From: George Bosilca (bosilca_at_[hidden])
Date: 2007-07-10 14:44:04


I always use MX_RCACHE=2 for both MTL and BTL. So far I didn't had
any problems with it.

   george.

On Jul 10, 2007, at 2:37 PM, Brian Barrett wrote:

> 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
>
>
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