pti: move libpti.so driver to the custom $libdir/pti folder

[dvrogozh]

With: a928b93

Install the following dependencies:

$ docker run -it --rm ubuntu:26.04
# apt-get update && apt-get install git cmake make g++ gcc pkg-config python3 libze-dev
# apt-get install dpclang-6

Configure and install the project:

# cd sdk
# cmake -B _build -DCMAKE_C_COMPILER=dpclang -DCMAKE_CXX_COMPILER=dpclang++ \
    -DCMAKE_INSTALL_PREFIX=/opt/_install .
# make -j16 -C _build/ install

The installation will look like the following:

# tree /opt/_install/
/opt/_install/
|-- include
|   `-- pti
|       |-- pti.h
|       |-- pti_callback.h
|       |-- pti_driver_levelzero_api_ids.h
|       |-- pti_export.h
|       |-- pti_metrics.h
|       |-- pti_metrics_scope.h
|       |-- pti_runtime_sycl_api_ids.h
|       |-- pti_version.h
|       `-- pti_view.h
|-- lib
|   |-- cmake
|   |   `-- pti
|   |       |-- PtiConfig.cmake
|   |       |-- PtiConfigVersion.cmake
|   |       |-- PtiTargets-release.cmake
|   |       `-- PtiTargets.cmake
|   |-- libpti.so
|   |-- libpti_view.so -> libpti_view.so.0
|   |-- libpti_view.so.0 -> libpti_view.so.0.17.0
|   `-- libpti_view.so.0.17.0
`-- share
    `-- doc
        `-- pti
            `-- LICENSE.txt

9 directories, 18 files

The libpti.so library is unversioned and as far as I know is kind of a driver/plugin for libpti_view.so which is an actual user entry point. As such:

1. libpti.so should not be installed to $libdir (at least by default) and instead placed into $libdir/pti instead
2. libpti_view.so must use hardcoded path to load the libpti.so, for example by doing dlopen("./pti/libpti.so"). This also can be handled in other ways such as adding /etc/pti.conf file which would hold PTI configuration such as driver location. Or hardcoding the location during build time configuration. However, I believe that using location relative to libpti_view.so should be a good starting point.

CC: @mschilling0 @frenchwr

[mschilling0]

Note:

on Windows, we're using a semi-hardcoded path, we get the path to pti_view.dll (via Win API call) then using that to find pti.dll in the lib directory.

Will something similar work for Linux? And maybe also a custom environment variable for testing.

[dvrogozh]

on Windows, we're using a semi-hardcoded path, we get the path to pti_view.dll (via Win API call) then using that to find pti.dll in the lib directory.

I think we are taking about the same thing. That's what I meant under dlopen("./pti/libpti.so"). Probably I should better write something like dlopen(dirof("libpti_view.so.x") + "/pti/libpti.so"). Having variable to be able to change this location is also fine.