llama.cpp

6f8895fe - opencl: general flash attention decode performance optimizations (#25366)

opencl: general flash attention decode performance optimizations (#25366) * opencl: vec flash-attention decode kernels for f16/q8_0/q4_0 KV * opencl: improve non FA KQ mv kernels * opencl: tweaks for multiquery FA * opencl: some tweaks for FA q1 kernels * opencl: FA with DK=DV=512 for gemma-4 * opencl: various fixes * opencl: cleanup * opencl: fix FA decode crash for DK=512 (gemma-4) The DK=512 decode-only program does not create the f32_f16 prefill kernel, so the compiled check in ensure_fa_variant never hit and supports_op gave inconsistent answers for the same op. block_n is also unset for DK=512 decode; guard it to avoid an out-of-range read at dispatch. * opencl: run DK=512 FA decode on CPU DK=512 decode is bandwidth-bound and faster on the CPU than the GPU, increasingly so with depth. Decline it in supports_op; prefill stays on the GPU. * opencl: compile MQ_GQA=8 FA kernels in a minimal program The full program compiled with -D MQ_GQA=8 runs the Adreno compiler out of memory at DK>=256. Only the vec_mq kernels are used from this program, so compile it with FA_MQ_ONLY, which excludes everything else. Also include the program name in the compile error log. * opencl: remove stray token in flash_attn_f32_f16.cl A stray "." broke the f32_f16 program build. * opencl: split f16-KV FA decode finer (FD_KV_PER_SPLIT_F16) The 2048 default under-fills the GPU on single-query f16-KV decode; use 512 for f16 KV to get more splits. Quantized KV keeps 2048. --------- Co-authored-by: Li He <lih@qti.qualcomm.com>