Difference between pages "Template:PageNeedsUpdates" and "News:CPU FLAGS X86"
m (fix format) |
|||
Line 1: | Line 1: | ||
{{News | |||
|Summary=CPU_FLAGS_X86 are being introduced to group together USE flags managing CPU instruction sets. | |||
|News Format=Extended | |||
|News Category=General | |||
|Author=Mgorny | |||
|Publication Status=Published | |||
|Publication Date=2015/01/31 | |||
}} | |||
Hello, everyone. | |||
The USE flags corresponding to the instruction sets and other features specific to the x86 (including x86-64) architecture are being moved into a separate USE flag group called CPU_FLAGS_X86. | |||
In order not to lose CPU-specific optimizations, users will be required to update their make.conf (and package.use) file. For example, if the following USE flags were present: | |||
{{file|name=/etc/portage/make.conf|desc=The original make.conf flags|body= | |||
USE="mmx mmxext sse sse2 sse3" | |||
}} | |||
Those flags need to be copied into: | |||
{{file|name=/etc/portage/make.conf|desc=The new make.conf flags|body= | |||
CPU_FLAGS_X86="mmx mmxext sse sse2 sse3" | |||
}} | |||
Please note that the same CPU_FLAGS_X86 variable is used both on 32-bit and 64-bit x86 (amd64) systems. | |||
When in doubt, you can consult the flag descriptions using one of the commonly available tools, e.g. ''equery uses'' from gentoolkit: | |||
{{console|body= | |||
$##i## equery uses media-video/ffmpeg | |||
}} | |||
Most of the flag names match /proc/cpuinfo names, with the notable exception of SSE3 which is called 'pni' in /proc/cpuinfo (please also do not confuse it with distinct SSSE3). | |||
To help users enable the correct USE flags, we are providing a Python script that generates the correct value using /proc/cpuinfo. It can be found in the {{Package|app-portage/cpuinfo2cpuflags}} package: | |||
{{console|body= | |||
###i## emerge -1v app-portage/cpuinfo2cpuflags | |||
$##i## cpuinfo2cpuflags-x86 | |||
}} | |||
In order to ensure safe migration and maintain compatibility with external repositories, it is recommended to preserve the old USE settings for a period of one year or until no package of interest is still using them. | |||
{{NewsFooter}} |
Latest revision as of 08:59, January 31, 2015
CPU FLAGS X86
CPU_FLAGS_X86 are being introduced to group together USE flags managing CPU instruction sets.
By Mgorny / January 31, 2015Hello, everyone.
The USE flags corresponding to the instruction sets and other features specific to the x86 (including x86-64) architecture are being moved into a separate USE flag group called CPU_FLAGS_X86.
In order not to lose CPU-specific optimizations, users will be required to update their make.conf (and package.use) file. For example, if the following USE flags were present:
/etc/portage/make.conf
- The original make.conf flagsUSE="mmx mmxext sse sse2 sse3"
Those flags need to be copied into:
/etc/portage/make.conf
- The new make.conf flagsCPU_FLAGS_X86="mmx mmxext sse sse2 sse3"
Please note that the same CPU_FLAGS_X86 variable is used both on 32-bit and 64-bit x86 (amd64) systems.
When in doubt, you can consult the flag descriptions using one of the commonly available tools, e.g. equery uses from gentoolkit:
user $ equery uses media-video/ffmpeg
Most of the flag names match /proc/cpuinfo names, with the notable exception of SSE3 which is called 'pni' in /proc/cpuinfo (please also do not confuse it with distinct SSSE3).
To help users enable the correct USE flags, we are providing a Python script that generates the correct value using /proc/cpuinfo. It can be found in the No results package:
root # emerge -1v app-portage/cpuinfo2cpuflags user $ cpuinfo2cpuflags-x86
In order to ensure safe migration and maintain compatibility with external repositories, it is recommended to preserve the old USE settings for a period of one year or until no package of interest is still using them.