-mtune

Purpose

Tunes architecture-dependent performance enhancements, such as scheduling, to enable programs to run optimally on a specific hardware architecture.

Defaults

-mtune=power7 or -mtune=pwr7 when no valid -mcpu setting is in effect. Otherwise, the default value depends on the -mcpu setting. Find details in Table1: Acceptable -mcpu and -mtune combinations.

Parameters

The following suboptions allow you to specify a particular architecture for the compiler to target for best performance:

native

Optimizations are tuned for the platform on which the application is compiled.

powerpc|ppc

Optimizations are tuned for the 32-bit PowerPC® hardware platforms.

powerpc64|ppc64

Optimizations are tuned for the 64-bit PowerPC hardware platforms.

power7|pwr7

Optimizations are tuned for the Power7 or Power7+ hardware platforms.

power8|pwr8

Optimizations are tuned for the Power8 hardware platform.

power9|pwr9

Optimizations are tuned for the Power9 hardware platform.

power10|pwr10

Optimizations are tuned for the Power10 hardware platform.

Usage

Use a combination of the -mcpu and -mtune options when you want your program to run on more than one architecture but be tuned for a particular architecture.

The -mtune option can improve performance by arranging (scheduling) the generated machine instructions to take maximum advantage of hardware features, such as cache size and pipelining.

Although changing the -mtune setting might impact the performance of the resulting executable, it does not affect whether the executable can be executed correctly on a particular hardware platform.

Predefined macros

None.

Related information

• -mcpu
• Specifying compiler options for architecture-specific compilation