linux-yocto/tools/power/cpupower

The cpupower package consists of the following elements:

requirements

On x86 pciutils is needed at runtime (-lpci). For compilation pciutils-devel (pci/pci.h) and a gcc version providing cpuid.h is needed. For both it's not explicitly checked for (yet).

libcpupower

"libcpupower" is a library which offers a unified access method for userspace tools and programs to the cpufreq core and drivers in the Linux kernel. This allows for code reduction in userspace tools, a clean implementation of the interaction to the cpufreq core, and support for both the sysfs and proc interfaces [depending on configuration, see below].

compilation and installation

There are 2 output directories - one for the build output and another for the installation of the build results, that is the utility, library, man pages, etc...

default directory

In the case of default directory, build and install process requires no additional parameters:

build

$ make

The output directory for the 'make' command is the current directory and its subdirs in the kernel tree: tools/power/cpupower

install

$ sudo make install

'make install' command puts targets to default system dirs:

---

| Installing file | System dir |

| libcpupower | /usr/lib |

| cpupower | /usr/bin |

| cpufreq-bench_plot.sh | /usr/bin |

| man pages | /usr/man |

To put it in other words it makes build results available system-wide, enabling any user to simply start using it without any additional steps

custom directory

There are 2 make's command-line variables 'O' and 'DESTDIR' that setup appropriate dirs: 'O' - build directory 'DESTDIR' - installation directory. This variable could also be setup in the 'CONFIGURATION' block of the "Makefile"

build

$ make O=<your_custom_build_catalog>

Example: $ make O=/home/hedin/prj/cpupower/build

install

$ make O=<your_custom_build_catalog> DESTDIR=<your_custom_install_catalog>

Example: $ make O=/home/hedin/prj/cpupower/build DESTDIR=/home/hedin/prj/cpupower \

install

Notice that both variables 'O' and 'DESTDIR' have been provided. The reason is that the build results are saved in the custom output dir defined by 'O' variable. So, this dir is the source for the installation step. If only 'DESTDIR' were provided then the 'install' target would assume that the build directory is the current one, build everything there and install from the current dir.

The files will be installed to the following dirs:

---

| Installing file | System dir |

| libcpupower | ${DESTDIR}/usr/lib |

| cpupower | ${DESTDIR}/usr/bin |

| cpufreq-bench_plot.sh | ${DESTDIR}/usr/bin |

| man pages | ${DESTDIR}/usr/man |

If you look at the table for the default 'make' output dirs you will notice that the only difference with the non-default case is the ${DESTDIR} prefix. So, the structure of the output dirs remains the same regardles of the root output directory.

clean and uninstall

'clean' target is intended for cleanup the build catalog from build results 'uninstall' target is intended for removing installed files from the installation directory

default directory

This case is a straightforward one: $ make clean $ make uninstall

custom directory

Use 'O' command line variable to remove previously built files from the build dir: $ make O=<your_custom_build_catalog> clean

Example: $ make O=/home/hedin/prj/cpupower/build clean

Use 'DESTDIR' command line variable to uninstall previously installed files from the given dir: $ make DESTDIR=<your_custom_install_catalog>

Example: make DESTDIR=/home/hedin/prj/cpupower uninstall

running the tool

default directory

$ sudo cpupower

custom directory

When it comes to run the utility from the custom build catalog things become a little bit complicated as 'just run' approach doesn't work. Assuming that the current dir is '<your_custom_install_catalog>/usr', issuing the following command:

$ sudo ./bin/cpupower will produce the following error output: ./bin/cpupower: error while loading shared libraries: libcpupower.so.1: cannot open shared object file: No such file or directory

The issue is that binary cannot find the 'libcpupower' library. So, we shall point to the lib dir: sudo LD_LIBRARY_PATH=lib64/ ./bin/cpupower

THANKS

Many thanks to Mattia Dongili who wrote the autotoolization and libtoolization, the manpages and the italian language file for cpupower; to Dave Jones for his feedback and his dump_psb tool; to Bruno Ducrot for his powernow-k8-decode and intel_gsic tools as well as the french language file; and to various others commenting on the previous (pre-)releases of cpupower.

    Dominik Brodowski