The chatr command changes a program's
internal attributes and can be used to modify the data page size
for a specific executable. The larger the page size, the fewer virtual-to-
physical, memory-page translations your process has to undergo.
This can have a dramatic effect (sometimes 2X) on
the performance of data-intensive (RAM) applications.
For programs that use less than 64 MB of data space, use
to allow
the page size to grow from 16 Kb to 32 Kb or 64 Kb and up to the maximum
it needs.
For programs that use more than 64 MB of data space, use
This command causes the a.out to start
with large pages (64 MB) and limits the page size to 64 MB, so that
page sizes that are too large cannot cause a premature out of memory
condition. For example, if you are using a 1GB page size and only
have 0.99 GB left, the page allocation may fail (you run out of
memory even though you have almost a gigabyte left).
For over 2GB of RAM, use chatr to enable
the use of data space above 2GB:
chatr +q3p
enable (only needed on a 32-bit a.out)
For over 3GB of RAM, use:
chatr +q4p enable (only needed on a 32-bit
a.out)
See the chatr(1) man page for more information.
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