Extended SYCL oneDNN SDPA to non-FP16 KV caches (Q4_0–Q8_0 and FP32) (#25874)
* sycl: extend oneDNN SDPA to Q4_0-Q8_0 and F32 KV caches
Extends the oneDNN SDPA path (PR #25222) to handle non-F16 KV caches by
dequantizing or converting K/V to dense FP16 on-device before feeding
them into the SDPA graph. The fused systolic kernel then runs identically
to the native FP16 path.
Supported KV types:
- Q4_0, Q4_1, Q5_0, Q5_1, Q8_0: to_fp16_sycl / to_fp16_nc_sycl
- F32: cont_to_f16_sycl<float>
- BF16 and IQ types are excluded (no conversion kernel available)
Gate: non-F16 requires K >= 1024 and Q >= 32 (prefill only).
F16 KV runs at any length (existing behavior).
Also includes the stream sync fix (stream->wait_and_throw() unconditional,
PR #25741 by @malsbat) and removal of V_is_K_view aliasing (K and V are
always dequantized to separate buffers).
Co-Authored-By: Claude <noreply@anthropic.com>
* docs: drop GGML_SYCL_FA_DEBUG from SYCL.md (not shipped in this PR)
Co-Authored-By: Claude <noreply@anthropic.com>
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Co-authored-by: Claude <noreply@anthropic.com>