The LIBHEAP64 runtime option controls the
allocation of heap storage that is used by Language Environment for AMODE
64 applications. Storage that is unrestricted can be located anywhere
in 64-bit addressable storage.
The default value for AMODE 64
applications is LIBHEAP64(1M,1M,FREE,16K,8K,FREE,8K,4K,FREE).
Syntax
.-KEEP-.
>>-+-LIBHEAP64-+--(--+--------+--,--+--------+--,--+------+----->
'-LH64------' '-init64-' '-incr64-' '-FREE-'
.-KEEP-.
>--,--+--------+--,--+--------+--+------+--,--+--------+--,----->
'-init31-' '-incr31-' '-FREE-' '-init24-'
.-KEEP-.
>--+--------+--+------+--)-------------------------------------><
'-incr24-' '-FREE-'
- init64
- Determines the initial allocation of library heap storage that
is obtained above the 2G bar. Specify this value as nM
bytes of storage. If a value of 0 or less is specified, the default
is used.
- incr64
- Determines the minimum size of any subsequent increment to the
library heap storage obtained above the 2G bar. Specify this value
as nM bytes of storage. If a value less
than 0 is specified, the default is used.
- KEEP
- Specifies that an increment to library heap storage is not released
when the last of the storage within that increment is freed.
- FREE
- Specifies that an increment to library heap storage is released
when the last of the storage within that increment is freed.
- init31
- Determines the minimum initial size of library heap storage that
is obtained above the 16M line and below the 2G bar. This value can
be specified as n, nK,
or nM number of bytes. If 0 is specified,
the initial storage is obtained on the first use and is based on the
increment size. The amount of allocated storage is rounded up to the
nearest multiple of 8 bytes.
- incr31
- Determines the minimum size of any subsequent increment to library
heap storage that is obtained above the 16M line and below the 2G
bar. This value can be specified as n, nK,
or nM number of bytes. The amount of allocated
storage is rounded up to the nearest multiple of 8 bytes.
- init24
- Determines the minimum initial size of library heap storage that
is obtained below the 16M line. This value can be specified as n, nK,
or nM number of bytes. If 0 is specified,
the initial storage is obtained on the first use and is based on the
increment size. The amount of allocated storage is rounded up to the
nearest multiple of 8 bytes.
- incr24
- Determines the minimum size of any subsequent increment to library
heap storage that is obtained below the 16M line. This value can be
specified as n, nK,
or nM number of bytes. The amount of allocated
storage is rounded up to the nearest multiple of 8 bytes.
Performance consideration
You can improve
performance with the LIBHEAP64 runtime option by
specifying values that minimize the number of times the operating
system allocates storage. See RPTSTG for
information about how to generate a report you can use to determine
the optimum values for the LIBHEAP64 runtime option.