GitLab

* Bring back escape valve for llm libraries

If the new discovery logic picks the wrong library, this gives users the
ability to force a specific one using the same pattern as before. This
can also potentially speed up bootstrap discovery if one of the libraries
takes a long time to load and ultimately bind to no devices.  For example
unsupported AMD iGPUS can sometimes take a while to discover and rule out.

* Bypass extra discovery on jetpack systems

On at least Jetpack6, cuda_v12 appears to expose the iGPU, but crashes later on in
cublasInit so if we detect a Jetpack, short-circuit and use that variant.

This variable isn't currently documented or intended as something the user can
override, but if the user happens to set OLLAMA_LIBRARY_PATH we were doubling
this in the subprocess environment which will cause problems with the new
bootstrap discovery logic.

The CUDA APIs for reporting free VRAM are useless on NVIDIA iGPU
systems as they only return the kernels actual free memory and ignore
buff/cache allocations which on a typical system will quickly fill up
most of the free system memory.  As a result, we incorrectly think
there's very little available for GPU allocations which is wrong.

Wrong index variable was used.

This revamps how we discover GPUs in the system by leveraging the Ollama
runner.  This should eliminate inconsistency between our GPU discovery and the
runners capabilities at runtime, particularly for cases where we try to filter
out unsupported GPUs.  Now the runner does that implicitly based on the actual
device list.  In some cases free VRAM reporting can be unreliable which can
leaad to scheduling mistakes, so this also includes a patch to leverage more
reliable VRAM reporting libraries if available.

Automatic workarounds have been removed as only one GPU leveraged this, which
is now documented. This GPU will soon fall off the support matrix with the next
ROCm bump.

Additional cleanup of the scheduler and discovery packages can be done in the
future once we have switched on the new memory management code, and removed
support for the llama runner.