How to enable ccache on Linux

Question

There is very little documentation on enabling ccache on GNU/Linux. Here is a response from launchpad.net:

At the moment, I think the best way to enable ccache is to add "/usr/lib/ccache" to the front of your path. If you want to enable it for all users by default, change the PATH variable in /etc/environment.

Can someone give me more information on enabling ccache?

Solution 1

Download latest version of ccache for better performance.

After Downloading, Follow the steps as mentioned below:

A) Tar the file using the following command :

 $tar -xvf ccache-3.2.4.tar.bz2
 
 Note : I'm using ccache 3.2.4 Version.You can download the latest one.

B) Go inside ccache-3.2.4 folder and run the following commands:

 $./configure
 $./make 
 $ sudo make install

C) Go to your .bashrc and insert the following :

 export CCACHE_DIR=/home/user_name/.ccache
 export CCACHE_TEMPDIR=/home/user_name/.ccache

 Note : Fill user_name with your User Name

D) Save your Bashrc and source it

 $ source ~/.bashrc

E) To check ccache is working or not type :

 ccache -M 10G : To Set the ccache Size to 10GB

F) To check ccache is working or not type :

 ccache -s : To check ccache statistics 

Solution 2

The ccache manual has a section called Run modes which describes the official ways of activating ccache, so I suggest reading the manual.

Also, as you already noted, Linux distributions often set up a /usr/lib/ccache directory which is designed to be prepended to PATH.

Solution 3

There are at least two methods:

i) Override the CC, CXX, ... flags in a Makefile. Within the R framework, a system and optional user configuration file is read, and I simply set

VER=4.7
CC=ccache gcc-$(VER)
CXX=ccache g++-$(VER)
SHLIB_CXXLD=g++-$(VER)
FC=ccache gfortran
F77=ccache gfortran

which also allows me to switch back and forth between gcc versions. Now all compilations involving R use ccache.

ii) For other uses, I have deployed the fact that /usr/local/bin/ is checked prior to /usr/bin. So one can do

root@max:/usr/local/bin# ls -l gcc
lrwxrwxrwx 1 root root 15 Jan 27 11:04 gcc -> /usr/bin/ccache
root@max:/usr/local/bin# ./gcc --version
gcc (Ubuntu/Linaro 4.7.2-2ubuntu1) 4.7.2
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

root@max:/usr/local/bin# 

and now gcc is invoked via ccache:

edd@max:/tmp$ cp -vax ~/src/progs/C/benfordsLaw.c .
`/home/edd/src/progs/C/benfordsLaw.c' -> `./benfordsLaw.c'
edd@max:/tmp$ time /usr/local/bin/gcc -c benfordsLaw.c 

real    0m0.292s
user    0m0.052s
sys     0m0.012s
edd@max:/tmp$ time /usr/local/bin/gcc -c benfordsLaw.c 

real    0m0.026s
user    0m0.004s
sys     0m0.000s
edd@max:/tmp$ 

Solution 4

Another possibility (instead of export CC=ccache commented by Keltar), if $HOME/bin/ is listed in your $PATH before /usr/bin/, would be to make a symlink

 ln -s /usr/bin/ccache $HOME/bin/gcc

Then every execvp(3) of gcc would find that symlink

View more solutions