Ccache

From ArchWiki
Jump to: navigation, search

Related articles

There is a wonderful tool for gcc called ccache. You can read about it at their home page.

If you are always compiling the same programs over and over again — such as trying out several kernel patches, or testing your own development — then ccache is perfect. While it may take a few seconds longer to compile a program the first time with ccache, subsequent compiles will be much, much faster.

Installation

Install the ccache package.

Enable ccache for makepkg

To enable ccache when using makepkg edit /etc/makepkg.conf. In BUILDENV uncomment ccache (remove the exclamation mark) to enable caching. For example:

/etc/makepkg.conf
BUILDENV=(fakeroot !distcc color ccache check !sign)

Enable for command line

If you are compiling your code from the command line, and not building packages, then you will still want to use ccache to help speed things up.

For that, you need to change your $PATH to include ccache's binaries before the path to your compiler:

$ export PATH="/usr/lib/ccache/bin/:$PATH"

You may want to add this line to your ~/.bashrc file for regular usage.

Enable with colorgcc

Since colorgcc is also a compiler wrapper, some care needs to be taken to ensure each wrapper is called in the correct sequence.

export PATH="/usr/lib/colorgcc/bin/:$PATH"    # As per usual colorgcc installation, leave unchanged (don't add ccache)
export CCACHE_PATH="/usr/bin"                 # Tell ccache to only use compilers here

Then colorgcc needs to be told to call ccache instead of the real compiler. Edit /etc/colorgcc/colorgccrc and change the /usr/bin paths to /usr/lib/ccache/bin for all the compilers in /usr/lib/ccache/bin:

/etc/colorgcc/colorgccrc
g++: /usr/lib/ccache/bin/g++
gcc: /usr/lib/ccache/bin/gcc
c++: /usr/lib/ccache/bin/g++
cc: /usr/lib/ccache/bin/cc
g77:/usr/bin/g77
f77:/usr/bin/g77
gcj:/usr/bin/gcj

Misc

Change the cache directory

You may want to move the cache directory to a faster location than the default ~/.ccache directory, like an SSD or a ramdisk.

To change the cache location:

$ export CCACHE_DIR=/ramdisk/ccache

Disable the cache via environment

If you wish to disable CCache only in the current shell you can set:

$ export CCACHE_DISABLE=1

CLI

You can use the command-line utility ccache to show a statistics summary:

$ ccache -s

or clear the cache completely:

$ ccache -C

See also