Just a few more important points that I forgot to mention.

This work has been helped and guided by Rainer. He will also continue to use the tool for further research. :-)

This new component can be enabled via option --enable-memchecker. When disabled, there won't be any influence for Open MPI and application.

The patch has been tested based on a version of Open MPI a few month ago, but it should be easy to move to the latest OMPI trunk. I will make a bitbucket branch for merging it back.

I would like explain more details in the call today.

On 2012-10-08 3:05 PM, Shiqing Fan wrote:

What:

A new memory checking tool named MemPin was developed based on the Intel Pin framework. It uses a callback mechanism to do the similar tasks as Valgrind Memcheck. The new tool is tiny and flexible, and user may implement his own callback function for different purposes.

The basic idea here for Open MPI is to watch over the communication buffers. Every access to the buffers will be detected, and for specific memory operation (read/write), a memory check callback will be triggered.

Only the required memory will be taken care of, so the shadow memory can be kept to be as small as possible. The implemented shadow memory for Open MPI is handled in bit-wise, i.e. every byte of memory has 2 bits of shadow (4 different states. This doesn't provide bit-wise validity of the memory like Valgirnd, where every byte of memory has 9 bits of shadow. However, the shadow memory for this new tool is extensible.

Several predefined macros that may be used in user application and Open MPI:

   MEMPIN_RUNNING_WITH_PIN: Checks whether the user application is running under MemPin and Pin

   MEMPIN_REG_MEM_WATCH: Registers the memory entry for specific memory operation

   MEMPIN_UPDATE_MEM_WATCH: Updates the memory entry parameters for specific memory operation

   MEMPIN_UNREG_MEM_WATCH: Unregisters one memory entry

   MEMPIN_UNREG_ALL_MEM_WATCH: Unregisters all the memory entries

   MEMPIN_SEARCH_MEM_INDEX: Returns the memory entry index from the memory address storage

   MEMPIN_PRINT_CALLSTACK: Prints the current callstack to standard output or a file

The new component mempin will have the same memchecker API as valgrind component.

WHY:

This new implementation has similar functionalities as Valgrind Memcheck, but it is lightweight, faster, extensible and flexible. It also supports for Windows platforms.

WHERE:
      opal/mca/memchecker/
      ompi/include/ompi/memchecker.h or another header file.
      ompi/mca/pml/ob1    several memchecker macro need to be updated.

WHEN:
     If everything is fine, probably some time next week or later this month.

We probably can also discuss it in the next teleconf.

Thanks,
Shiqing
-- 
---------------------------------------------------------------
Shiqing Fan
High Performance Computing Center Stuttgart (HLRS)
Tel: ++49(0)711-685-87234      Nobelstrasse 19
Fax: ++49(0)711-685-65832      70569 Stuttgart
http://www.hlrs.de/organization/people/shiqing-fan/
email: fan@hlrs.de
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-- 
---------------------------------------------------------------
Shiqing Fan
High Performance Computing Center Stuttgart (HLRS)
Tel: ++49(0)711-685-87234      Nobelstrasse 19
Fax: ++49(0)711-685-65832      70569 Stuttgart
http://www.hlrs.de/organization/people/shiqing-fan/
email: fan@hlrs.de