Programming with Judy

Tuning HP-UX Memory Access
Compiler Switch
Chapter 5 57
Compiler Switch
The -N C compiler switch (32-bit only) is passed through to the linker
and directs it to lower the start of the heap to immediately after the text
(code) segment. This allows you almost a 1GB larger data segment, but
makes your a.out unsharable. See ld(1) for more information.
Swap Partition
This is the disk partition used for a system swap area. If your swap area
is too small, the HP-UX kernel reserves some real memory to make sure
it never “starves” for memory. This memory reservation takes away
memory from user applications. To avoid this, set up a swap area that is
the size of your RAM (either as a dedicated disk partition or through
SAM). For example, if you have 2GB of RAM, use a 2GB swap area.
In summary
To ensure that Judy has good memory performance and access, use
the following to tune your HP-UX system:
•The chatr command
• Kernel tunable parameters: maxdsize or maxdsiz_64bit, and
dbc_max_pct
• -N C compiler switch (32-bit only)
• Disk partition for swapping