Large Language Model (LLM) inference is rapidly becoming a core datacenter service, yet current serving stacks keep the host CPU on the critical path for orchestration and token-level control. This makes LLM performance sensitive to CPU interference, undermining application colocation and forcing operators to reserve CPU headroom, leaving substantial capacity unutilized. We introduce Blink, an end-to-end serving architecture that removes the host CPU from the steady-state inference path by redistributing responsibilities across a SmartNIC and a GPU. Blink offloads request handling to the SmartNIC, which delivers inputs directly into GPU memory via RDMA, and replaces host-driven scheduling with a persistent GPU kernel that performs batching, scheduling, and KV-cache management without CPU involvement. Evaluated against TensorRT-LLM, vLLM, and SGLang, Blink outperforms all baselines even in isolation, reducing pre-saturation P99 TTFT by up to 8.47× and P99 TPOT by up to 3.40×, improving decode throughput by up to 2.1×, and reducing energy per token by up to 48.6%. Under CPU interference, Blink maintains stable performance, while existing systems degrade by up to two orders of magnitude.
Figures & tables
Figure 1. Achieved throughput of 4 LLM serving systems on Qwen-3 30B-A3B (MoE) at 4 req/s offered load, under isolated and colocated execution. Blink is unaffected by colocation while baselines degrade. Annotations show the colocated-to-isolated throughput ratio.
Baseline
Interference
12 ×
24 ×
Throughput (tok/s)
7475
4554
1961
Mean TTFT (ms)
73.7
4865
16552
P99 TTFT (ms)
150
6366
20959
Mean TPOT (ms)
13.0
13.6
14.8
P99 TPOT (ms)
14.4
18.0
32.1
Table 1. Impact of colocation on vLLM serving latency and microarchitectural counters. H100, Llama-3 8B, 7req/s , w/ CUDA Graphs.
4 KB pages
2 MB pages
1 GB (interferer)
Throughput (tok/s)
4813
5053
45405298
P50 TTFT (ms)
12276
12612
1257815205
P99 TTFT (ms)
29208
26780
2919132270
P50 TPOT (ms)
19.8
19.9
17.919.6
P99 TPOT (ms)
25.0
25.4
27.230.5
P99 ITL (ms)
70.1
72.2
73.284.8
Table 2. Ablation: page size and gigantic pages do not restore isolation (H100, CUDA Graphs enabled, 128 requests at 7req/s ). All runs include interference. Isolation baseline: 7697tok/s throughput, 13.5ms mean TPOT , 5.9% LLC miss rate.
Isolation
Interference
Δ %
Total completed requests
502
415
-17.3 %
Mean throughput (tok/s)
4130.50
3457.85
-16.3 %
Mean throughput (req/s)
8.37
6.92
-17.3 %
P50 TTFT (ms)
10052.08
12539.18
+24.7 %
P99 TTFT (ms)
22409.94
23968.67
+7.0 %
P99.9 TTFT (ms)
23925.64
25732.75
+7.6 %
Table 3. Core pinning (6 dedicated cores) under pbzip2 interference. ShareGPT workload, Poisson arrivals at 12req/s , 60s window.
Cache ways
1
3
5
7
12
LLC miss rate (%)
57.6
26.6
11.1
7.0
6.8
IPC
1.16
1.31
1.48
1.52
1.55
LLC stall cycles
3169 M
1750 M
741 M
428 M
442 M
dTLB load misses
7.4 M
7.1 M
7.1 M
7.0 M
7.0 M
walk_active
895 M
596 M
462 M
420 M
400 M
P99 TTFT (ms)
29675
26627
27146
26352
26157
Table 4. Effect of CAT cache-way allocation under interference (H100, CUDA Graphs, 128 requests at 7req/s , dedicated CPU cores). LLC miss rate drops 8.5× , yet P99 ITL is virtually unchanged.
Figure 2. Architecture of Blink . After one-time initialization, the host CPU is idle; the steady-state inference path involves only the GPU and the DPU. Filled circles trace the lifecycle of a single request.
Figure 3. Normalized makespan: GPU-resident vs. CPU-resident scheduling on Qwen3-32B (N × I → O denotes N requests, I input tokens, O output tokens). CPU vs. GPU-resident scheduler makespan Bar chart comparing normalized makespan. The CPU-resident scheduler is 1.16–1.70x slower across four workload configurations.
Figure 4. Tokenization latency on BlueField-3 ARM A78 cores ( Blink ) vs. Intel Xeon (HuggingFace, llama.cpp). Labels show speedup relative to HuggingFace. Tokenization latency comparison Bar chart comparing tokenization latency for HuggingFace, llama.cpp, and \systemnameacross input lengths of 10–2048 tokens. \systemnameis 8–19.7x faster than HuggingFace.
Component
Specification
GPU
NVIDIA H100 (96 GB HBM3)
CPU
2 × Intel Xeon Gold 6336Y (96 cores @ 2.40 GHz),
DVFS disabled, governor: performance
DRAM
256 GB DDR5
Network
ConnectX-6 (200 Gbps)
DPU
BlueField-3 (16 ARM Cortex-A78, 32 GB)
Table 5. Hardware configuration.
Model
System
Geo. P99 TTFT
Geo. P99 TPOT
Tput at sat.
Llama-3 8B λ≤12
Blink
653.8
15.1
11.87
TRT-LLM
880.0
17.7
10.80
vLLM
1309.6
24.2
9.12
SGLang
1747.1
30.7
7.88
Phi-4 15B λ≤7
Blink
1109.4
25.0
6.72
TRT-LLM
1453.8
29.8
6.42
Table 6. Pre-saturation summary over the Blink -defined operating range. Repeated runs are averaged per load to match the figures. TTFT and TPOT are in milliseconds; Tput@sat is achieved throughput at Blink ’s saturation point. Best values per model are boldfaced.
Figure 5. P99.9 tail latency for Qwen-3 32B (isolated). Although P99 latencies are near-parity, P99.9 reveals a consistent Blink advantage across all baselines that grows with load. P99.9 TTFT and TPOT for Qwen-3 32B P99.9 TTFT and TPOT latency comparison between \systemname, TensorRT-LLM, vLLM, and SGLang on Qwen-3 32B under isolated execution.
Figure 6. P99 tail latency across four models. Top row (a–d): TTFT; bottom row (e–h): TPOT. Solid lines show isolated execution; dashed lines show CPU interference. Within Blink ’s operating range, Blink maintains a flatter latency envelope and near-overlapping isolated and interference curves, whereas baseline systems queue earlier and suffer severe tail inflation under co-location. P99 TTFT and TPOT under isolated and interference conditions P99 TTFT and TPOT latency across model architectures under both isolated and interference conditions.
Model
System
Geo. P99 TTFT
Geo. P99 TPOT
Tput at sat.
Llama-3 8B λ≤12
Blink
652.8 [1.00]
15.2 [1.00]
11.83 [1.00]
TRT-LLM
16574 [18.84]
196.6 [11.10]
4.13 [0.38]
vLLM
14563 [11.12]
178.2 [7.35]
4.00 [0.44]
SGLang
14728 [8.43]
177.3 [5.77]
3.78 [0.48]
Phi-4 15B λ≤7
Blink
1023.2 [0.92]
24.4 [0.98]
6.77 [1.01]
TRT-LLM
15496 [10.66]
183.7 [6.17]
2.62 [0.41]
Table 7. Same pre-saturation summary as Table 6 , but under CPU interference. Bracketed terms show interference / isolation; throughput brackets report retention at Blink ’s saturation point. Raw latencies are in milliseconds and throughput in requests/s. Best raw values per model are boldfaced.
Figure 7. Throughput across four models. Solid lines show isolated execution; dashed lines show CPU interference. Blink reaches the latest or tied-latest saturation point in isolation and preserves its plateau under interference, while baselines either saturate earlier or collapse to much lower plateaus. Throughput under isolation and interference for all four models Throughput under isolation and interference for all four models.
Figure 8. Energy per token under (a) isolation and (b) colocated interference. Energy per token for four models under isolation and interference Bar chart comparing energy per token (mJ/tok) for \systemname, vLLM, TensorRT-LLM, and SGLang across LLaMA 3 8B, Phi-4, Qwen3 30B-A3B, and Qwen3 32B under isolation and co-located interference.
Appendix figures & tables8 assets
Supplementary material from the paper’s appendix.
Appendix
Model
System
P50 TTFT
Mean TTFT
P50 TPOT
Mean TPOT
Llama-3 8B
Blink
41.8
116.9
7.5
8.2
TRT-LLM
72.3
170.1
8.6
9.6
vLLM
111.1
276.1
11.0
12.4
SGLang
240.3
507.1
12.9
14.5
Phi-4 15B
Blink
105.8
258.8
13.4
14.1
TRT-LLM
153.1
355.7
15.2
16.3
Appendix
Table B.1 . Geometric-mean latency (ms) over Blink ’s operating range under isolated execution. Best values per model are boldfaced. Operating ranges: λ≤12 (Llama-3 8B), ≤7 (Phi-4 15B), ≤2 (Qwen-3 32B), ≤4 (Qwen-3 30B-A3B).
Model
System
Decode tok/s
Prefill tok/s
Llama-3 8B
Blink
3880
595
TRT-LLM
3535
582
vLLM
2930
564
SGLang
2638
553
Phi-4 15B
Blink
2177
465
TRT-LLM
2044
459
Appendix
Table B.2 . Token-level throughput (tok/s) at Blink ’s saturation point under isolated execution. Best values per model are boldfaced.
Figure C.1 . Maximum serviceable load (95% throughput retention threshold) per system and model. Higher is better. Blink achieves the highest serviceable load on every model; on Qwen-3 30B-A3B the gap is largest under isolation, and under interference Blink retains its full isolated capacity while baselines lose 60–65% on Llama-3 8B. Serviceable load bar charts under isolated and interference Two bar charts showing maximum serviceable load for all systems across four models: (a) isolated and (b) interference conditions.
Figure D.1 . P99.9 tail latency across four models. Top row (a–d): TTFT; bottom row (e–h): TPOT. Solid lines show isolated execution; dashed lines show CPU interference. Blink sustains lower P99.9 latency across the full load sweep on all four models, with the largest margin on the MoE model (Qwen-3 30B-A3B). Baseline dashed curves separate sharply from their isolated counterparts, while Blink ’s remain nearly overlapping. P99.9 latency for all models P99.9 TTFT and TPOT across four models under isolated and interference conditions.
Figure D.2 . P95 latency across four models. Top row (a–d): TTFT; bottom row (e–h): TPOT. Solid lines show isolated execution; dashed lines show CPU interference. The relative system ordering is consistent with the P99 results in the main paper, confirming that Blink ’s advantage is structural rather than an artifact of rare outliers. P95 latency for all models P95 TTFT and TPOT across four models under isolated and interference conditions.
Figure D.3 . Median (P50) latency across four models. Top row (a–d): TTFT; middle row (e–h): TPOT; bottom row (i–l): ITL. Solid lines show isolated execution; dashed lines show CPU interference. Blink achieves the lowest or near-lowest median across all metrics, with differences compressing on the GPU-bound Qwen-3 32B. Under interference, baseline medians inflate substantially while Blink ’s remain stable. P50 latency for all models P50 TTFT, TPOT, and ITL across four models under isolated and interference conditions.
Figure D.4 . Mean latency across four models. Top row (a–d): TTFT; middle row (e–h): TPOT; bottom row (i–l): ITL. Solid lines show isolated execution; dashed lines show CPU interference. The mean tracks between P50 and P95 due to heavy-tailed queuing distributions; system ordering remains consistent with tail percentile results. Baseline means inflate by 3–18 × under interference while Blink ’s stays within 1.0–1.15 × . Mean latency for all models Mean TTFT, TPOT, and ITL across four models under isolated and interference conditions.
Figure E.1 . Token-level throughput across four models. Top row (a–d): prefill throughput (prompt tokens/s); bottom row (e–h): decode throughput (output tokens/s). Solid lines show isolated execution; dashed lines show CPU interference. Blink ’s GPU-resident scheduling eliminates per-iteration CPU round-trips, yielding higher sustained decode throughput. Under interference, baseline decode throughput collapses while Blink ’s plateau is preserved. Prefill and decode throughput for all models Prefill and decode token throughput across four models under isolated and interference conditions.
Although existing frameworks for large language model (LLM) inference on CPUs are mature, they fail to fully exploit the computation potential of many-core CPU platforms. Many-core CPUs are widely deployed in web servers and high-end networking devices, and are typically organized into multiple NUMA nodes that group cores and memory. Current frameworks largely overlook the substantial overhead of cross-NUMA memory access, limiting inference scalability and intelligence enabling on such platforms. To address this limitation, we build ArcLight, a lightweight LLM inference architecture designed from the ground up for many-core CPUs. ArcLight integrates efficient memory management and thread scheduling, and introduces finely controlled tensor parallelism to mitigate the cross-node memory access wall. Experimental results show that ArcLight significantly surpasses the performance ceiling of mainstream frameworks, achieving up to 46% higher inference throughput. Moreover, ArcLight maintains compatibility with arbitrary CPU devices. ArcLight is publicly available at https://github.com/OpenBMB/ArcLight.
Yuzhuang Xu, Xu Han, Yuxuan Li +1
Harbin Institute of Technology, Harbin, China · Tsinghua University, Beijing, China
LLM serving systems are provisioned for peak load to meet strict latency targets, leaving substantial GPU compute idle whenever traffic falls below peak. We present DeltaServe, a host-agnostic co-serving design that converts this idle inference capacity into LoRA fine-tuning throughput while preserving inference service-level objectives (SLOs). DeltaServe integrates with existing inference engines through a compact hook interface that requires only multi-LoRA batching support. It exploits the shared execution structure of inference prefill and LoRA fine-tuning forward passes, and uses an SLO-aware scheduler to admit and execute fine-tuning only when sufficient inference headroom is available. The scheduler is driven by a CUDA-graph-aware latency model calibrated offline and refined online. We integrate DeltaServe with vLLM, SGLang, and S-LoRA. On a production trace from Company X, DeltaServe on vLLM delivers 2.9x higher fine-tuning throughput than LLMStation at 100% inference SLO compliance, versus 85% for LLMStation. It also achieves 39% higher fine-tuning throughput than a baseline running vLLM+torchtune, using no additional hardware and maintaining full SLO compliance.
On-device inference offers privacy, offline use, and instant response, but consumer hardware restricts large language models (LLMs) to low throughput and capability. To overcome this challenge, we present prima.cpp, a distributed on-device inference system that runs 30-70B LLMs on consumer home clusters with mixed CPUs/GPUs, insufficient RAM/VRAM, slow disks, Wi-Fi links, and heterogeneous OSs. We introduce pipelined-ring parallelism (PRP) to overlap disk I/O with compute and communication, and address the prefetch-release conflict in mmap-based offloading. We further propose Halda, a heterogeneity-aware scheduler that co-optimizes per-device CPU/GPU workloads and device selection under RAM/VRAM constraints. On four consumer home devices, a 70B model reaches 674 ms/token TPOT with <6% memory pressure, and a 32B model with speculative decoding achieves 26 tokens/s. Compared with llama.cpp, exo, and dllama, our proposed prima.cpp achieves 5-17 times lower TPOT, supports fine-grained model sizes from 8B to 70B, ensures broader cross-OS and quantization compatibility, and remains OOM-free, while also being Wi-Fi tolerant, privacy-preserving, and hardware-independent. The code is available at https://github.com/OpenCPIL/prima.cpp.