Archived

This repository has been archived as it is no longer functional with the latest versions of KISS. Due to major changes in the hook behaviour, it isn't possible for this repo to work without forking every single package that requires workarounds.

kissLTO

A KISS repository for building with -O3, Graphite, and LTO optimizations, the KISS version of gentooLTO. This is a continuation of the kiss_optim repo by admicos.

Usage

• Add this repository to KISS_PATH such that it takes precedence over other repos:

export KISS_PATH="/path/to/kissLTO/repo:$KISS_PATH"

• Create a symlink at the top level of this repository pointing to the official KISS repositories:

cd /path/to/kissLTO
ln -sf /path/to/main-repo ./kiss-repo

• (IMPORTANT) Set a KISS_HOOK to automatically work around build failures in packages:

export KISS_HOOK=/path/to/kissLTO/kiss-hook

• Modify build flags (Initial):

export CFLAGS="-O3 -pipe -march=native -mtune=native -fno-math-errno -fdevirtualize-at-ltrans -fno-semantic-interposition -fipa-pta -flto=auto -fuse-linker-plugin"
export CXXFLAGS="$CFLAGS"
export LDFLAGS="-Wl,-O1 -Wl,--as-needed $CFLAGS"

• Re-build gcc and enable Graphite optimizations:

CFLAGS="$CFLAGS -fgraphite-identity -floop-nest-optimize"`
export CXXFLAGS="$CFLAGS"
export LDFLAGS="-Wl,-O1 -Wl,--as-needed $CFLAGS"

• Re-build binutils and enable the gold linker:

CFLAGS="$CFLAGS -fuse-ld=gold"`
export CXXFLAGS="$CFLAGS"
export LDFLAGS="-Wl,-O1 -Wl,--as-needed $CFLAGS"

• The final shell .profile should look like this:

export CFLAGS="-O3 -pipe -march=native -mtune=native -fno-math-errno -fdevirtualize-at-ltrans -fno-semantic-interposition -fipa-pta -flto=auto -fuse-linker-plugin -fgraphite-identity -floop-nest-optimize -fuse-ld=gold"
export CXXFLAGS="$CFLAGS"
export LDFLAGS="-Wl,-O1 -Wl,--as-needed $CFLAGS"

• Do a full system rebuild to allow all packages to pick up the new optimizations.

Packages

Some packages are forked to this repository for further optimizations:

• binutils: Forked to enable the gold linker.

• ffmpeg, x264: Forked for build fixes when using LTO.

• firefox, gcc, python, zstd: Built with PGO.