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DEEPSEEK V4 INFERENCE GETS 50% SPEEDUP; LLAMA.CPP AND VLLM BOTH SHIPPING OPTIMIZED PATHS
By RepoJournal · Filed · About Local LLMs
DeepSeek V4 speculative decode just went from nice-to-have to standard: llama.cpp landed MTP and DSpark support with roughly 50% speedup [ref:3], vLLM hardened its KV cache coordinator for the same models [ref:7], and Metal got native hyper-connection ops [ref:5].
This is the biggest single inference win across the stack in months. The llama.cpp DSpark path [2] lets you export separate draft heads for speculative decoding, while the Metal implementation of DeepSeek V4's specialized hyper-connection operations [3] unlocks GPU-native inference without performance cliffs. vLLM's KV connector bugfix [7] was the linchpin: it correctly propagates EAGLE/MTP state across merged cache groups, fixing a subtle coordinator failure that would have silently tanked throughput on multi-GPU setups. On the parallel track, vLLM shipped a CPU MoE migration to modular-kernel experts [6], eliminating three legacy code paths and unifying quantized and unquantized backends. llama.cpp also added SILU backward ops for Metal [4], and Qwen3 chat parsing now handles both `</think>` and `<tool_call>` reasoning delimiters [5]. SGLang landed DSPARK sampling support in graph-folded mode [9], broadcast-optimized vision embeddings [10], and hardened its spec fixture teardown [11], while vLLM added jina-embeddings-v5 support with encoder-only dispatch [8]. Both projects shipped 69 commits and 69 PRs across 10 releases in the last 24 hours.
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Action items
- → Rebuild llama.cpp with Metal if you run inference on Apple Silicon - DSpark support is live [ref:3] [ref:4] ggml-org/llama.cpp [immediate]
- → Upgrade vLLM if running DeepSeek V4 multi-GPU - KV cache coordinator fix is essential [ref:7] vllm-project/vllm [immediate]
- → Monitor SGLang DSPARK folded sampling under load - new code path, gate with SGLANG_DSPARK_FOLDED_SAMPLING=AUTO [ref:13] sgl-project/sglang [monitor]
References
- [1] DeepseekV4 MTP + DSpark ↗ ggml-org/llama.cpp
- [2] convert: add option to create separate dspark GGUF ↗ ggml-org/llama.cpp
- [3] metal: implement DeepSeek V4 hyper-connections ↗ ggml-org/llama.cpp
- [4] metal : add SILU_BACK (#25982) ggml-org/llama.cpp
- [5] chat : add qwen3 specialized parser ↗ ggml-org/llama.cpp
- [6] [CPU] Migrate unquantized MoE to the modular-kernel experts structure ↗ vllm-project/vllm
- [7] [Bugfix][KV Connector] Propagate EAGLE state across merged Mooncake store groups ↗ vllm-project/vllm
- [8] [Model] Support jina-embeddings-v5-text-nano (EuroBERT encoder backbone) ↗ vllm-project/vllm
- [9] [Spec] Support sampling in the DSPARK graph-folded draft proposal ↗ sgl-project/sglang
- [10] [Perf] Broadcast single-image DP vision embedding instead of pad-to-max all-gather ↗ sgl-project/sglang
- [11] [CI] Graceful teardown for kv_canary and EAGLE spec fixtures ↗ sgl-project/sglang