mbox series

[v3,0/4] Add SWIG Bindings to libcpupower

Message ID 20240905021916.15938-1-jwyatt@redhat.com (mailing list archive)
Headers show
Series Add SWIG Bindings to libcpupower | expand

Message

John B. Wyatt IV Sept. 5, 2024, 2:19 a.m. UTC
SWIG is a tool packaged in Fedora and other distros that can generate
bindings from C and C++ code for several languages including Python,
Perl, and Go. Providing bindings for scripting languages is a common feature
to make use of libraries more accessible to more users and programs. My team
specifically wants to expand the features of rteval. rteval is a Python program
used to measure real time performance. We wanted to test the effect of enabling
some levels of idle-stat to see how it affects latency, and didn't want to
reinvent the wheel. Since SWIG requires the .o files created by libcpupower at
compilation it makes sense to include this in the cpupower directory so that
others can make use of them.

The V3 of this patchset includes:
* renaming header messages as requested and adding people to Cc as
requested
* moving the stub (dummy) commit to the front of the patchset
* small punctuation fixes

The V2 of this patchset includes:
* the full definition of libcpupower headers that is needed for the bindings
* dummy implementation in C of a function listed in the header of libcpupower
(requested by Shuah Khan)
* test_raw_pylibcpupower.py demonstrates an example of using the bindings
* adding myself and John Kacur to the cpupower section of the maintainers file
(requested by Shuah Khan)
* addressed review comments about doc, makefile, and maintainers file
* small style and other fixes

The name raw_pylibcpupower is used because a wrapper `pylibcpupower` may be
needed to make the bindings more 'pythonic' in the future. The bindings folder
is used because Go or Perl bindings may be useful for other users in the
future.

Note that while SWIG itself is GPL v3+ licensed; the resulting output, the
bindings code, has the same license as the .o files used to generate the
bindings (GPL v2 only). Please see
https://swig.org/legal.html
and
https://lore.kernel.org/linux-pm/Zqv9BOjxLAgyNP5B@hatbackup/#t
for more details on the license.

Sincerely,
John Wyatt
Software Engineer, Core Kernel
Red Hat

John B. Wyatt IV (4):
  pm:cpupower: Add missing powercap_set_enabled() stub function
  pm:cpupower: Add SWIG bindings files for libcpupower
  pm:cpupower: Include test_raw_pylibcpupower.py
  MAINTAINERS: Add Maintainers for SWIG Python bindings

 MAINTAINERS                                   |   3 +
 .../power/cpupower/bindings/python/.gitignore |   8 +
 tools/power/cpupower/bindings/python/Makefile |  31 +++
 tools/power/cpupower/bindings/python/README   |  59 +++++
 .../bindings/python/raw_pylibcpupower.i       | 247 ++++++++++++++++++
 .../bindings/python/test_raw_pylibcpupower.py |  42 +++
 tools/power/cpupower/lib/powercap.c           |   8 +
 7 files changed, 398 insertions(+)
 create mode 100644 tools/power/cpupower/bindings/python/.gitignore
 create mode 100644 tools/power/cpupower/bindings/python/Makefile
 create mode 100644 tools/power/cpupower/bindings/python/README
 create mode 100644 tools/power/cpupower/bindings/python/raw_pylibcpupower.i
 create mode 100755 tools/power/cpupower/bindings/python/test_raw_pylibcpupower.py

Comments

Shuah Khan Sept. 6, 2024, 1:03 a.m. UTC | #1
On 9/4/24 20:19, John B. Wyatt IV wrote:
> SWIG is a tool packaged in Fedora and other distros that can generate
> bindings from C and C++ code for several languages including Python,
> Perl, and Go. Providing bindings for scripting languages is a common feature
> to make use of libraries more accessible to more users and programs. My team
> specifically wants to expand the features of rteval. rteval is a Python program
> used to measure real time performance. We wanted to test the effect of enabling
> some levels of idle-stat to see how it affects latency, and didn't want to
> reinvent the wheel. Since SWIG requires the .o files created by libcpupower at
> compilation it makes sense to include this in the cpupower directory so that
> others can make use of them.
> 
> The V3 of this patchset includes:
> * renaming header messages as requested and adding people to Cc as
> requested
> * moving the stub (dummy) commit to the front of the patchset
> * small punctuation fixes
> 
> The V2 of this patchset includes:
> * the full definition of libcpupower headers that is needed for the bindings
> * dummy implementation in C of a function listed in the header of libcpupower
> (requested by Shuah Khan)
> * test_raw_pylibcpupower.py demonstrates an example of using the bindings
> * adding myself and John Kacur to the cpupower section of the maintainers file
> (requested by Shuah Khan)
> * addressed review comments about doc, makefile, and maintainers file
> * small style and other fixes
> 
> The name raw_pylibcpupower is used because a wrapper `pylibcpupower` may be
> needed to make the bindings more 'pythonic' in the future. The bindings folder
> is used because Go or Perl bindings may be useful for other users in the
> future.
> 
> Note that while SWIG itself is GPL v3+ licensed; the resulting output, the
> bindings code, has the same license as the .o files used to generate the
> bindings (GPL v2 only). Please see
> https://swig.org/legal.html
> and
> https://lore.kernel.org/linux-pm/Zqv9BOjxLAgyNP5B@hatbackup/#t
> for more details on the license.
> 
> Sincerely,
> John Wyatt
> Software Engineer, Core Kernel
> Red Hat
> 
> John B. Wyatt IV (4):
>    pm:cpupower: Add missing powercap_set_enabled() stub function
>    pm:cpupower: Add SWIG bindings files for libcpupower
>    pm:cpupower: Include test_raw_pylibcpupower.py
>    MAINTAINERS: Add Maintainers for SWIG Python bindings
> 
>   MAINTAINERS                                   |   3 +
>   .../power/cpupower/bindings/python/.gitignore |   8 +
>   tools/power/cpupower/bindings/python/Makefile |  31 +++
>   tools/power/cpupower/bindings/python/README   |  59 +++++
>   .../bindings/python/raw_pylibcpupower.i       | 247 ++++++++++++++++++
>   .../bindings/python/test_raw_pylibcpupower.py |  42 +++
>   tools/power/cpupower/lib/powercap.c           |   8 +
>   7 files changed, 398 insertions(+)
>   create mode 100644 tools/power/cpupower/bindings/python/.gitignore
>   create mode 100644 tools/power/cpupower/bindings/python/Makefile
>   create mode 100644 tools/power/cpupower/bindings/python/README
>   create mode 100644 tools/power/cpupower/bindings/python/raw_pylibcpupower.i
>   create mode 100755 tools/power/cpupower/bindings/python/test_raw_pylibcpupower.py
> 

Applied the series for Linux 6.12-rc1 to

https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux.git cpupower branch

I chose to walk through the steps without installing SWIG
to see what make would do.

Some things to improve:

Running make in tools/power/cpupower/bindings/python directory without
installing SWIG gives me the following errors:

make: python-config: No such file or directory
swig -python raw_pylibcpupower.i
make: swig: No such file or directory
make: *** [Makefile:27: raw_pylibcpupower_wrap.c] Error 127

I think it would be good to provide better help message walking
user through installing the dependencies.

Documentation/Makefile is a good example to look at for useful
message on the dependencies to be installed.

You can send me patch on top of
https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux.git cpupower branch

thanks,
-- Shuah