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From: George Bosilca (bosilca_at_[hidden])
Date: 2007-07-10 16:04:31


I did see this warnings a while ago. But, it didn't happened on the
last few weeks. I prefer not to set it automatically, or have to add
a new MCA parameter. That way, we cannot be blamed for anything. The
first thing the users will notice, is a degradation of the
performances. Then they complain about it, and there we can just say
"it's in the doc, please add MCX_RCACHE=2 to your shell
initialization scripts". And we look like heroes :)

   george.

On Jul 10, 2007, at 2:58 PM, Scott Atchley wrote:

> Tim, starting with the recently released 1.2.1, it is the default.
>
> George, do you see the warning or no?
>
> Scott
>
> On Jul 10, 2007, at 2:52 PM, Tim Prins wrote:
>
>> Is this something that Open MPI should be setting automatically?
>>
>> Tim
>>
>> On Tuesday 10 July 2007 02:44:04 pm George Bosilca wrote:
>>> 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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