makepkg-optimize

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makepkg-optimize^AUR is a collection of supplemental tidy, buildenv, and executable scripts for pacman which provide macros for several kinds of optimization in the build() and package() stages.

Note: As with any package in the Arch User Repository, makepkg-optimize^AUR has no official support. You should read, and you may post comments on its AUR page.

Installation

Install makepkg-optimize^AUR and, to make optimizations available, install their backends: openmp, upx, optipng, and svgo^AUR.

Configuration

makepkg-optimize^AUR generates a redundant configuration file, /etc/makepkg-optimize.conf, from your current makepkg.conf(5) configuration.

This file lists supplementary COMPILE FLAGS, BUILD ENVIRONMENT options, GLOBAL PACKAGE OPTIONS, PACKAGE OUTPUT options, and COMPRESSION DEFAULTS, all of which are disabled by default.

Warning: Some packages may fail to build with certain optimizations and over-optimization may cause problems for some programs--such as decreased performance and segmentation faults.

Build an optimized package

After selecting your preferred optimizations, pass the configuration file when building:

$ makepkg -c --config /etc/makepkg-optimize.conf

Note: Profile-guided optimization requires that a package be built and installed twice. The first phase initiates profile generation in $PROFDEST/pkgbase.gen; the second moves them to $PROFDEST/pkgbase.used and applies them.

Tip: Use -c with makepkg to prevent packages reusing stale optimization flags. See Makepkg#Usage.

Build an optimized package in a clean chroot

Alternatively, makepkg-optimize can be used to build optimized packages within a chroot.

Chroot setup

After setting up a chroot, a few additional steps are needed.

Install makepkg-optimize and backends

First, install some of the backends for the optimization macros to the base chroot:

$ arch-nspawn "$CHROOT"/root pacman -S openmp upx optipng

Then download and build makepkg-optimize^AUR and svgo^AUR.

To install them in the base chroot, copy their package files into it and install them, e.g.:

# cp svgo-1.2.2-2-any.pkg.tar.xz "$CHROOT"/root/root/
$ arch-nspawn "$CHROOT"/root pacman -U /root/svgo-1.2.2-2-any.pkg.tar.xz

Warning: This voids the warranty on your "clean" chroot!

Create a PGO cache

To use PGO, create a folder in the same place, inside and outside of the chroot, to store profiles:

# mkdir -m 777 {"$CHROOT"/{root,"$USER"},}/mnt/pgo

Then edit $CHROOT/root/etc/makepkg-optimize.conf and set PROFDEST=/mnt/pgo.

Using the chroot

Note: When updating the chroot, AUR packages have to be updated manually.

Build a package

First, edit $CHROOT/root/etc/makepkg-optimize.conf and select your preferred optimizations.

When building, pass the configuration file to makepkg:

$ makechrootpkg -c -r "$CHROOT" -- -c --config /etc/makepkg-optimize.conf

Building with PGO

After the first building phase, bind the PGO cache:

# mount -o bind {,"$CHROOT"/root}/mnt/pgo
# mount -o bind "$CHROOT"/{root,"$USER"}/mnt/pgo

Tip: Use fstab to bind these folders at boot.

Install the package and test-run its executables.

Note: Profiles are generated on program exit(). Persistent daemons, such as systemd, may require a reboot to produce profiles. If you have rebooted, be sure to rebind the PGO cache before rebuilding.

After thoroughly utilizing the software, rebuild and reinstall the package.