[BUG]: THRUST_DEVICE_SYSTEM is missing from ccmake

[bernhardmgruber]

Is this a duplicate?

• I confirmed there appear to be no duplicate issues for this bug and that I agree to the Code of Conduct

Type of Bug

Something else

Component

Thrust

Describe the bug

Previously, configuring CCCL with cmake would expose the cache variable THRUST_DEVICE_SYSTEM in the cmake tui (ccmake). The variable seems to have disappeared.

This is unfortunate, since it makes switching backends inside a build directory unnecessarily harder.

How to Reproduce

Run from a CCCL git clone:

mkdir build_dir
cd build_dir
cmake ..
ccmake ..

Shows the following Thrust-related variables:

 THRUST_CPP_DIALECT               17
 THRUST_DISPATCH_TYPE             Dynamic
 THRUST_ENABLE_EXAMPLES           ON
 THRUST_ENABLE_EXAMPLE_FILECHEC   OFF
 THRUST_ENABLE_HEADER_TESTING     ON
 THRUST_ENABLE_MULTICONFIG        OFF
 THRUST_ENABLE_RDC_TESTS          ON
 THRUST_ENABLE_TESTING            ON
 THRUST_FORCE_RDC                 OFF
 Thrust_ENABLE_INSTALL_RULES      ON

Expected behavior

The variable THRUST_DEVICE_SYSTEM should be displayed as it used to be.

Reproduction link

No response

Operating System

No response

nvidia-smi output

No response

NVCC version

No response

[alliepiper]

That variable is hidden when THRUST_ENABLE_MULTICONFIG=ON, since it'd otherwise conflict with the multiconfig state.

[alliepiper]

It looks like some code may have bit-rotted away, the definitions of those options are missing. I'll put up a PR soon.

[alliepiper]

It's worth pointing out that the singleconfig stuff isn't really used or tested anymore and is likely to have more issues.

Rather than changing the system in a build directory, why not just use the all-dev preset and just build the targets from the host/device/dialect triple you're interested it?

[bernhardmgruber]

It's worth pointing out that the singleconfig stuff isn't really used or tested anymore and is likely to have more issues.

I could be convinced that we should drop the singleconfig stuff in the interest of a simpler build system.

Rather than changing the system in a build directory, why not just use the all-dev preset and just build the targets from the host/device/dialect triple you're interested it?

That's a valid workflow for developing. However, when I test, profile, debug, hunt bugs, etc. I tend to try through different configurations while repeating the same commands over and over again. I find it easier if the target name does not change every time I change the configuration.

But again, if the benefit of dropping singleconfig mode is lage, I can cope.