metal : add MoE and SSM_CONV fusion optimizations (#28948)
* metal : add top-k MoE fusion
Adds a Metal fusion for SOFT_MAX + ARGSORT + GET_ROWS with optional
routing-weight normalization and scale, matching the top-k MoE fusion
available in the CUDA and Vulkan backends. The fused kernel writes the
selected expert ids and routing weights directly, eliding the separate
softmax, argsort, get-rows, sum-rows, clamp, div and scale kernels.
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : add MoE weighted reduction fusion
Fuses MUL(experts, weights) plus the expert VIEW/ADD chain into one kernel
that computes the weighted sum directly. The graph_optimize hook keeps the
expert and weight buffers alive until the fused output so the allocator cannot
reuse them while the kernel is still reading them.
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* tests : expose MoE weighted reduction in fusion baseline
Use 2 experts per token in the generated MoE test models so the Metal
MoE weighted reduction fusion (MUL + ADD) is exercised by test-fusion.
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : fuse RMS_NORM + SCALE
Adds NORM/RMS_NORM + SCALE fusion to the Metal backend by reusing the
norm+mul kernel with a scalar scale flag. Adds test coverage for both
NORM+SCALE and RMS_NORM+SCALE and regenerates the fusion baseline.
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : use function constant for RMS_NORM + SCALE
Replaces the runtime use_scale karg with a Metal function constant. The
norm+mul kernel is compiled with FC_norm_use_scale=false for MUL fusion and
FC_norm_use_scale=true for SCALE fusion, so the fused kernel has no runtime
branch.
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : use function constant for top-k MoE with_norm
Replaces the runtime with_norm karg with a Metal function constant. The
top-k MoE kernel is compiled separately for the normalized and non-normalized
routing variants, removing the runtime branch.
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : rename moe_weighted_reduction suffix to moe_reduce
Shortens the MoE weighted-reduction fusion identifiers, kernel, pipeline,
matcher, args struct, and test op name from moe_weighted_reduction to
moe_reduce.
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : add MUL_MAT + UNARY and MUL_MAT + ADD + UNARY fusion
Adds dense mat-vec activation fusion for sigmoid/silu and bias+softplus.
The mat-vec kernels apply the activation/bias epilogue via function
constants, avoiding the separate unary/add passes.
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : revert MUL_MAT + UNARY and MUL_MAT + ADD + UNARY fusion
The mat-vec activation fusion regressed decode throughput on Qwen3.6-35B-A3B
by ~8% (tg32 81.5 vs 88.5 t/s). The regression is caused by loss of
concurrency: the standalone unary kernels previously overlapped with other
mat-vec work, while fusing the activation into the mat-vec kernel serializes
it on the critical path.
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : add SSM_CONV + UNARY (silu) fusion
The SSM_CONV kernels apply silu directly via a function constant, eliding
the separate unary pass. Regenerates the fusion baseline.
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : address fusion review comments
- Fix declaration/table alignment
- Rename top-k MoE kargs fields to val_clamp / val_scale
- Move moe-reduce alloc-deps handling into a general fusion helper
- Remove the public moe-reduce matcher API
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : fix unused parameter in top-k MoE fusion check
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : guard SSM_CONV fusion lookup behind use_fusion
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : track all fused outputs in graph reorder
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : keep top-k MoE logits alive until fused output
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : refactor alloc deps to pattern-driven approach
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : check fused kernel destination in concurrency tracking
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* meta : forward graph_optimize to underlying backends
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : use vector for fusion table
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* meta : keep graph_optimize unimplemented
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* parallel : fix non-deterministic prompt selection
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* parallel : support dummy models and add global logits run hash
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : sync cross-device copies with destination completion event
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : avoid const_cast in fusion alloc deps
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : skip fusions with aliased sources
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : hide fusion pattern definition
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : use vector fusion op sequences
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : drop redundant struct keywords
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : add alloc deps comment separator
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : generalize fusion output memory ranges
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : rename fusion out_offsets to outs
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : avoid dst vector in memory range check
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : optimize fusion matching and multi-output handling
- use pointer arithmetic for fusion info count lookup
- avoid heap allocations in top-k MoE and MoE reduce pattern matchers
- use fusion outs for multi-output subgraph checks
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* Revert "parallel : support dummy models and add global logits run hash"
This reverts commit 57c7caf941c1b43c270fd5009c9f175063522e96.
* fusion : update MTL.csv
* metal : unroll constant loops in top-k MoE kernel
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : use function constants for top-k MoE n_expert and top_k
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : rename fusion kargs to scale and clamp
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* metal : use function constants for moe_reduce and ssm_conv
Assisted-by: pi:llama.cpp/DeepSeek-V4-Flash-Vision-Exp
* fusion : update MTL.csv
