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.
This will likely yield builds that have problems with unicode characters
but at least we can start testing the release while we try to find an
alternate clang compiler for windows, or mingw ships a fixed version.
As we automatically enable flash attention for more models, there
are likely some cases where we get it wrong. This allows setting
OLLAMA_FLASH_ATTENTION=0 to disable it, even for models that usually
have flash attention.
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.
The GGML CUDA backend allocates additional memory for intermediate
results during calculation. This memory isn't currently allocated
during worst case graph reservation and therefore not included in
scheduling. This means that as these buffers potentially grow
with context length, we could crash.
This extends the memory allocation system down layer from the GGML
graph to the CUDA layer, preallocating the worst case memory there
as well.
Fixes#11753
