Skip to content

CAUTION: This site hosts draft documentation for the next release. For published content of the latest release, visit www.eclipse.org/openj9/docs

-XXsetHWPrefetch

(AIX® only)

This option enables or disables hardware prefetch. Hardware prefetch can improve the performance of applications by prefetching memory. However, because of the workload characteristics of many Java™ applications, prefetching often has an adverse effect on performance.

Syntax

    -XXsetHWPrefetch=[none|os-default]
Setting Effect Default
none Disable yes
os-default Enable

The -XXsetHWPrefetch:none option disables hardware prefetch. Although you can disable hardware prefetch on AIX by issuing the command dscrctl -n -s 1, this command disables hardware prefetch for all processes, and for all future processes, which might not be desirable in a mixed workload environment. The -XXsetHWPrefetch:none option allows hardware prefetch to be disabled for individual VMs.

To enable hardware prefetch with the default value for the operating system, specify -XXsetHWPrefetch:os-default. Use this option only for applications that can obtain a performance gain from hardware prefetch.