opt-prefetch, Qopt-prefetch

Enables or disables prefetch insertion optimization.

IDE Equivalent

Windows: None

Linux: Optimization > Enable Prefetch Insertion

Mac OS X: Optimization > Enable Prefetch Insertion

Architectures

IA-32, Intel® 64, IA-64 architectures

Syntax

Linux and Mac OS X:

-opt-prefetch[=n]

-no-opt-prefetch

Windows:

/Qopt-prefetch[:n]

/Qopt-prefetch-

Arguments

n

Is the level of detail in the report. Possible values are:

0	Disables software prefetching. This is the same as specifying -no-opt-prefetch (Linux and Mac OS X) or /Qopt-prefetch- (Windows).
1 to 4	Enables different levels of software prefetching. If you do not specify a value for `n`, the default is 2 on IA-32 and Intel® 64 architecture; the default is 3 on IA-64 architecture. Use lower values to reduce the amount of prefetching.

Default

IA-64 architecture: -opt-prefetch or/Qopt-prefetch	On IA-64 architecture, prefetch insertion optimization is enabled.
IA-32 architecture and Intel® 64 architecture: -no-opt-prefetch or/Qopt-prefetch-	On IA-32 architecture and Intel® 64 architecture, prefetch insertion optimization is disabled.

Description

This option enables or disables prefetch insertion optimization. The goal of prefetching is to reduce cache misses by providing hints to the processor about when data should be loaded into the cache.

On IA-64 architecture, this option is enabled by default if you specify option O1 or higher. To disable prefetching at these optimization levels, specify -no-opt-prefetch (Linux and Mac OS X) or /Qopt-prefetch- (Windows).

On IA-32 architecture and Intel® 64 architecture, this option enables prefetching when higher optimization levels are specified.

Alternate Options

Linux and Mac OS X: -prefetch (this is a deprecated option)

Windows: /Qprefetch (this is a deprecated option)