memory.tex

刚才是说明 现在是安装程序在 LINUX环境下进行编程的MPICH安装文件

\startmanpage
\mantitle{Memory}{tex}{10/7/2002}
\manname{Memory}
--- Memory Management Routines 
\subhead{Rules for memory management}
\par
MPICH explicity prohibits the appearence of {\tt malloc}, {\tt free},
{\tt calloc}, {\tt realloc}, or {\tt strdup} in any code implementing a device or
MPI call (of course, users may use any of these calls in their code).
Instead, you must use {\tt MPIU{\tt \char`\_}Malloc} etc.; if these are defined
as {\tt malloc}, that is allowed, but an explicit use of {\tt malloc} instead of
{\tt MPIU{\tt \char`\_}Malloc} in the source code is not allowed.  This restriction is
made to simplify the use of portable tools to test for memory leaks,
overwrites, and other consistency checks.
\par
Most memory should be allocated at the time that {\tt MPID{\tt \char`\_}Init} is
called and released with {\tt MPID{\tt \char`\_}Finalize} is called.  If at all possible,
no other MPID routine should fail because memory could not be allocated
(for example, because the user has allocated large arrays after {\tt MPI{\tt \char`\_}Init}).
\par
The implementation of the MPI routines will strive to avoid memory allocation
as well; however, operations such as {\tt MPI{\tt \char`\_}Type{\tt \char`\_}index} that create a new
data type that reflects data that must be copied from an array of arbitrary
size will have to allocate memory (and can fail; note that there is an
MPI error class for out-of-memory).
\par
\subhead{Question}
Do we want to have an aligned allocation routine?  E.g., one that
aligns memory on a cache-line.
\endmanpage