PAGEFRAMESIZE64

Derivation: PAGE FRAME SIZE for AMODE64

PAGEFRAMESIZE64 specifies the preferred page frame size in virtual storage for HEAP64, LIBHEAP64, IOHEAP64, and STACK64 storage that is obtained during application initialization and runtime.

The default value for AMODE 64 applications is PAGEFRAMESIZE64=(4K,4K,4K,4K,4K,4K,4K)

Syntax

                           .-4K------------------.      
>>-+-PAGEFRAMESIZE64-+--(--+---------------------+--,----------->
   '-PAG64-----------'     '-heap64_frame_size64-'      

   .-4K------------------.     .-4K---------------------.      
>--+---------------------+--,--+------------------------+--,---->
   '-heap64_frame_size31-'     '-libheap64_frame_size64-'      

   .-4K---------------------.     .-4K--------------------.   
>--+------------------------+--,--+-----------------------+----->
   '-libheap64_frame_size31-'     '-ioheap64_frame_size64-'   

      .-4K--------------------.     .-4K-----------------.      
>--,--+-----------------------+--,--+--------------------+--)--><
      '-ioheap64_frame_size31-'     '-stack64_frame_size-'      

heap64_frame_size64

Specifies the preferred page frame size in virtual storage for initial heap storage allocation and any subsequent heap increments above the 2 GB bar. The page frame size can be specified as one of the following values:

4K

Requests the default 4 KB pages.

1M

Requests that 1 MB large pages be used, if available.

heap64_frame_size31

Specifies the preferred page frame size in virtual storage for initial heap storage allocation and any subsequent heap increments above the 16 MB line and below the 2 GB bar. The page frame size can be specified as one of the following values:

4K

Requests the default 4 KB pages.

1M

Requests that 1 MB large pages be used, if available.

libheap64_frame_size64

Specifies the preferred page frame size in virtual storage for initial library heap storage allocation and any subsequent library heap increments above the 2 GB bar. The page frame size can be specified as one of the following values:

4K

Requests the default 4 KB pages.

1M

Requests that 1 MB large pages be used, if available.

libheap64_frame_size31

Specifies the preferred page frame size in virtual storage for initial library heap storage allocation and any subsequent library heap increments above the 16 MB line and below the 2 GB bar. The page frame size can be specified as one of the following values:

4K

Requests the default 4 KB pages.

1M

Requests that 1 MB large pages be used, if available.

ioheap64_frame_size64

Specifies the preferred page frame size in virtual storage for initial I/O heap storage allocation and any subsequent I/O heap increments above the 2 GB bar. The page frame size can be specified as one of the following values:

4K

Requests the default of 4 KB pages.

1M

Requests that 1 MB large pages be used, if available.

ioheap64_frame_size31

Specifies the preferred page frame size in virtual storage for initial I/O heap storage allocation and any subsequent I/O heap increments above the 16 MB line and below the 2 GB bar. The page frame size can be specified as one of the following values:

4K

Requests the default 4 KB pages.

1M

Requests that 1 MB large pages be used, if available.

stack64_frame_size

Specifies the preferred page frame size in virtual storage for initial stack storage allocation above the 2 GB bar. The page frame size can be specified as one of the following values:

4K

Requests the default KB pages.

1M

Requests that 1 MB large pages be used, if available.

Usage notes

• You cannot set PAGEFRAMESIZE64 at the system level or region level.
• You cannot specify PAGEFRAMESIZE64 with the CEEBXITA assembler user exit interface.
• If 1 MB page frames are not available, the default 4 KB page frame size is used. No message is issued to indicate this behavior.
• Page frame sizes larger than 4 KB are not allowed below the 16 MB line. If a PAGEFRAMESIZE parameter specifies 1 MB but that storage type is allocated below the 16 MB line, then the default 4 KB page frames is used. No message is issued to indicate this behavior, and the runtime options report shows the value that was specified.
• If the heap64_frame_size64 or hlibheap64_frame_size64 option is specified as 1M, then the initial storage allocation for both requests 1 MB page frames. The previous two usage notes apply as well.
• For THREADSTACK64 storage, the default 4 KB page frame size is used.
• When running in a preinitialized AMODE 64 (CELQPIPI) environment with an @GETSTORE service routine, a flag is passed to indicate that storage was requested to be backed by 1 MB page frames. For more information about using 1 MB page frames with an @GETSTORE service routine, see z/OS V2R1.0 Language Environment Programming Guide for 64-bit Virtual Addressing Mode.

Performance considerations