TokenWeave Guide: Compute-Communication Overlap for LLMs
The Communication Wall in Distributed Tensor-Parallel Serving
Serving frontier large language models (LLMs)—such as LLaMA-3.3-70B, Qwen2.5-72B, and LLaMA-3.1-405B—inevitably requires distributed execution. Because modern foundation model weights and high-concurrency Key-Value (KV) cache buffers exceed the 80GB to 141GB High-Bandwidth Memory (HBM) capacity of a single accelerator, production serving engines (including vLLM, TensorRT-LLM, and SGLang) rely on Megatron-style Tensor Parallelism (TP) across 4x, 8x, or 16x GPU clusters interconnected via NVLink.
Under Tensor Parallelism, linear projection weights within each transformer layer are partitioned across GPUs:
- Multi-Head Self-Attention (MHA): Attention projection matrices ($W_Q, W_K, W_V$) are partitioned column-wise, while the output projection matrix ($W_O$) is partitioned row-wise. To compute the final attention output, the partial sums computed across all GPUs must be aggregated via a collective All-Reduce operation.
- Feed-Forward Network (FFN / MLP): The gate and up-projection matrices ($W_{\text{gate}}, W_{\text{up}}$) are partitioned column-wise, while the down-projection matrix ($W_{\text{down}}$) is partitioned row-wise. A second collective All-Reduce operation is required to aggregate intermediate activations before adding residual connections.
Across a modern 80-layer foundation model, a single forward pass requires 160 sequential All-Reduce collective communications.
+---------------------------------------------------------------------------------------------------------+
| THE TENSOR-PARALLEL ALL-REDUCE BOTTLENECK |
+---------------------------------------------------------------------------------------------------------+
| |
| STANDARD TENSOR-PARALLEL TRANSFORMER LAYER EXECUTION: |
| [ Attention GEMM ] ---> [ All-Reduce 1 ] ---> [ RMSNorm 1 ] ---> [ MLP GEMM ] ---> [ All-Reduce 2 ] |
| |
| LATENCY BREAKDOWN ON AN 8x NVIDIA H100 DGX SYSTEM: |
| - Matrix Multiply Computations (GEMM): ~55% of forward layer latency |
| - Collective Network Communications (All-Reduce): ~35% to 45% of forward layer latency |
| --> Up to nearly HALF of total serving time is spent waiting on GPU-to-GPU network synchronization! |
| |
| SYSTEM PROBLEMS WITH CONVENTIONAL OVERLAP ATTEMPTS: |
| 1. Small/Medium Token Barrier: GEMMs for 1K-4K tokens execute too quickly to hide NCCL transfers. |
| 2. Streaming Multiprocessor (SM) Contention: NCCL steals 20-30 SMs, slowing down parallel GEMMs. |
| 3. Memory Round-Trip Waste: All-Reduce writes to HBM, then RMSNorm reads it right back. |
+---------------------------------------------------------------------------------------------------------+ Why Existing Compute-Communication Overlap Attempts Fail
In distributed machine learning training, systems hide communication latency through double buffering and pipelined gradient synchronization. However, transferring these techniques to online inference has proven notoriously difficult:
- Short-to-Medium Sequence Lengths: While long prefill sequences (e.g., 32k+ tokens) possess large matrix dimensions that can hide communication latency, the vast majority of production serving occurs at short to medium sequence lengths (1,024 to 4,096 tokens) during prompt processing and batched autoregressive decoding. At these dimensions, GEMM operations finish in fractions of a millisecond—insufficient time to hide standard NCCL ring or tree collective communications.
- Streaming Multiprocessor (SM) Resource Contention: In modern GPU architectures, collective communications are not free background DMA copies. Standard NVIDIA Collective Communications Library (NCCL) kernels utilize significant numbers of GPU Streaming Multiprocessors (typically 20 to 30 SMs out of 132 SMs on an NVIDIA H100) to orchestrate data reduction and inter-GPU packet movement. When communication is run concurrently with matrix multiplication, NCCL and GEMM compete directly for register files, shared memory, and L2 cache, degrading the throughput of both operations.
- The Ignored Memory Bottleneck (RMSNorm): Prior systems (such as TileLink, NanoFlow, or Megatron-overlap) focused exclusively on overlapping GEMM computation with All-Reduce. However, they completely overlooked the memory-intensive operation that immediately follows every All-Reduce: Root Mean Square Normalization (RMSNorm). Standard frameworks execute All-Reduce, write the resulting reduced tensor back into global GPU High-Bandwidth Memory (HBM), and immediately launch an RMSNorm kernel to read the entire tensor back into registers, saturating the GPU memory bus with redundant memory round-trips.
To overcome these structural barriers, researchers from Microsoft Research India introduced TokenWeave at MLSys 2026. TokenWeave is the first distributed inference framework capable of achieving near-complete compute-communication overlap for sequence lengths as small as 1,024 tokens.
By combining fine-grained Token-Splitting, a novel Fused AllReduce–RMSNorm Kernel, and hardware-accelerated NVSHARP / Multimem primitives requiring only 2 to 8 SMs, TokenWeave delivers up to a 1.28x end-to-end latency speedup and 1.19x higher serving throughput on an 8x NVIDIA H100 DGX system.
Architectural Foundations of TokenWeave
TokenWeave restructures the execution timeline of tensor-parallel transformer layers by coordinating token sub-sequences and fusing communication directly into memory normalization.
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| TOKENWEAVE SYSTEM ARCHITECTURE |
+---------------------------------------------------------------------------------------------------------+
| |
| INPUT TOKEN SEQUENCE (Length L = 1,024 to 8,192 tokens) |
| +-------------------------------------------------------------------------------------------------+ |
| | 1. TOKEN-SPLITTING DECOMPOSITION: Split sequence L into two balanced token chunks: T_1 and T_2 | |
| +-------------------------------------------------------------------------------------------------+ |
| / \ |
| Token Chunk T_1 (Tokens 0 .. L/2) Token Chunk T_2 (Tokens L/2 .. L) |
| / \ |
| v v |
| +------------------------------------+ +------------------------------------+ |
| | 2. STREAM A (Compute Stream) | | 3. STREAM B (Communication Stream) | |
| | - Executes GEMM(T_1) on SMs | | - Idle during GEMM(T_1) | |
| | - Signals Stream B completion | | - Begins Fused AllReduce(T_1) | |
| | - Concurrently executes GEMM(T_2| <================> | - Overlaps with GEMM(T_2) | |
| +------------------------------------+ Cross-Stream Sync +------------------------------------+ |
| \ / |
| \ / |
| v v |
| +-------------------------------------------------------------------------------------------------+ |
| | 4. NOVEL FUSED ALLREDUCE-RMSNORM KERNEL (NVSHARP / Multimem Hardware Accelerated) | |
| | - Performs inter-GPU reduction across NVLink in SRAM registers | |
| | - Normalizes activations via RMSNorm in-register without writing to GPU HBM | |
| | - Minimal SM Footprint: Consumes only 2 to 8 SMs, leaving 95%+ of GPU SMs free for GEMMs | |
| +-------------------------------------------------------------------------------------------------+ |
| | |
| v |
| +-------------------------------------------------------------------------------------------------+ |
| | PROCEEDS TO NEXT TRANSFORMER LAYER WITH ZERO COMMUNICATION BUBBLE | |
| +-------------------------------------------------------------------------------------------------+ |
+---------------------------------------------------------------------------------------------------------+ The Three Core Innovations
TokenWeave is built upon three foundational mechanisms:
- Fine-Grained Token-Splitting: TokenWeave divides the input sequence of length $L$ into two balanced token chunks: $T_1$ and $T_2$. Because linear matrix projections operate independently across the token sequence dimension, GEMM for $T_1$ can execute independently of $T_2$. As soon as the GPU completes GEMM computation for $T_1$, its collective communication begins on an asynchronous stream, running concurrently with the ongoing GEMM computation of $T_2$.
- Novel Fused AllReduce–RMSNorm Kernel: In standard systems, All-Reduce writes the reduced output tensor to global HBM, and RMSNorm reads it back. TokenWeave fuses these two stages into a single cooperative kernel:
- Partial reduction sums received across NVLink are accumulated directly in warp registers and shared memory.
- The Root Mean Square normalization factor is computed on the fly within registers.
- The normalized activations are written to memory once, completely eliminating a redundant global memory read-and-write cycle.
- Hardware Multicast Acceleration (NVSHARP / Multimem): Modern NVIDIA architectures (Hopper H100, Blackwell B200) introduce hardware-level multicast and reduction primitives (
MultimemandNVSHARP). By exploiting these on-silicon fabric capabilities, TokenWeave implements its fused reduction kernel using only 2 to 8 Streaming Multiprocessors (SMs) on an 8x H100 system (compared to 20 to 30 SMs required by NCCL). This leaves over 95% of GPU SMs completely unconstrained to execute matrix multiplications without resource throttling.
The Mathematics of Token-Splitting and Overlap
To understand why TokenWeave succeeds where previous overlap techniques failed, let us examine the execution timing and overlap feasibility.
Traditional Non-Overlapped Execution (Total Time = T_GEMM + T_Comm + T_Norm):
[================= GEMM(L) =================][======= All-Reduce(L) =======][== RMSNorm(L) ==]
Total Latency: 1.00x (Baseline)
TokenWeave Overlapped Execution (Token-Splitting + Fused Kernel):
Stream A (GEMM): [==== GEMM(T_1) ====][==== GEMM(T_2) ====]
^
Stream B (Comm): [ Fused-AR-Norm(T_1) ][ Fused-AR-Norm(T_2) ]
| <--- Overlapped! -->|
Total Latency: 0.78x (1.28x Speedup, Communication Fully Hidden!) Analytical Cost Formulation
Consider a tensor-parallel linear layer with input activation tensor $X \in \mathbb{R}^{L \times D}$ partitioned across $P$ GPUs.
In standard execution: $$T_{\text{baseline}} = T_{\text{GEMM}}(L, D, D_{\text{out}}/P) + T_{\text{AllReduce}}(L \cdot D_{\text{out}}) + T_{\text{RMSNorm}}(L \cdot D_{\text{out}})$$
Under TokenWeave, the sequence length $L$ is split into two halves: $T_1 = L/2$ and $T_2 = L/2$. The execution timeline proceeds in three phases:
- Phase 1: Compute $\text{GEMM}(T_1)$, taking time $T_{\text{GEMM}}(L/2)$.
- Phase 2 (Concurrent Overlap): While Stream A computes $\text{GEMM}(T_2)$, Stream B executes $\text{Fused-AR-Norm}(T_1)$ across NVLink: $$T_{\text{phase_2}} = \max \left( T_{\text{GEMM}}(L/2), ; T_{\text{Fused-AR-Norm}}(L/2) \right)$$
- Phase 3: Stream B executes $\text{Fused-AR-Norm}(T_2)$, taking time $T_{\text{Fused-AR-Norm}}(L/2)$.
The total execution time becomes: $$T_{\text{TokenWeave}} = T_{\text{GEMM}}(L/2) + \max \left( T_{\text{GEMM}}(L/2), ; T_{\text{Fused-AR-Norm}}(L/2) \right) + T_{\text{Fused-AR-Norm}}(L/2)$$
Because $\text{GEMM}(L/2) + \text{GEMM}(L/2) \approx T_{\text{GEMM}}(L)$, whenever the fused communication duration $T_{\text{Fused-AR-Norm}}(L/2) \le T_{\text{GEMM}}(L/2)$, the communication overhead of the entire first half of the sequence is 100% hidden behind computation!
Furthermore, because the fused kernel eliminates the memory round-trip of RMSNorm, $T_{\text{Fused-AR-Norm}}$ is substantially faster than $T_{\text{AllReduce}} + T_{\text{RMSNorm}}$.
Fused AllReduce–RMSNorm: Bypassing Global Memory
The secret to TokenWeave’s extreme efficiency lies in how it normalizes data directly out of the communication reduction.
The Standard RMSNorm Memory Round-Trip
In standard transformer implementations, RMSNorm calculates: $$\text{RMSNorm}(y_i) = \frac{y_i}{\sqrt{\frac{1}{D} \sum_{j=1}^D y_j^2 + \epsilon}} \odot \gamma_i$$ where $y_i$ is the reduced activation vector and $\gamma_i$ is a learnable scaling parameter.
In conventional systems:
- All-Reduce worker threads sum partial vectors from all $P$ GPUs across NVLink.
- The reduced tensor $y$ is written to global GPU High-Bandwidth Memory (HBM) ($L \cdot D$ write bytes).
- The GPU issues an explicit kernel synchronization barrier.
- The separate RMSNorm kernel launches, reading the entire tensor $y$ from HBM into registers ($L \cdot D$ read bytes).
- The kernel computes variance, normalizes, and writes the final output back to HBM ($L \cdot D$ write bytes). Total memory traffic: $3 \times L \cdot D$ bytes transferred over the HBM bus.
+---------------------------------------------------------------------------------------------------------+
| CONVENTIONAL VS. TOKENWEAVE MEMORY TRAFFIC |
+---------------------------------------------------------------------------------------------------------+
| Conventional Pipeline: |
| [ Partial Sums on NVLink ] ---> [ Reduce ] ---> WRITE TO HBM (1x) |
| | |
| v Global Memory Barrier |
| READ FROM HBM (1x) ---> [ RMSNorm ] ---> WRITE TO HBM (1x)
| Total Global Memory Traffic: 3x Tensor Size |
+---------------------------------------------------------------------------------------------------------+
| TokenWeave Fused Pipeline: |
| [ Partial Sums on NVLink via Multimem ] ---> [ In-Register Reduction + In-Register RMSNorm ] |
| | |
| v Single Write |
| WRITE DIRECTLY TO HBM (1x) |
| Total Global Memory Traffic: 1x Tensor Size (66% reduction in global memory bandwidth!) |
+---------------------------------------------------------------------------------------------------------+ The In-Register Fused Reduction Mechanism
TokenWeave exploits NVIDIA Hopper and Blackwell hardware multicast capabilities (Multimem instructions):
- Threads load partial sums directly from neighboring GPU physical addresses via NVLink into thread registers.
- As reduction progresses across warps, the running sum of squares $\sum y_j^2$ is accumulated concurrently in registers using warp shuffle intrinsics (
__shfl_xor_sync). - Once the reduction of the token vector completes, the thread block evaluates the reciprocal square root in hardware.
- The normalized, scaled activation is written to global HBM once.
By fusing All-Reduce with RMSNorm, TokenWeave eliminates two full global memory round-trips, slashing memory bus traffic by 66% and accelerating the combined operation by up to 40%.
Step-by-Step Implementation: Building a TokenWeave Pipelined Engine
To understand how TokenWeave orchestrates token-splitting, multi-stream CUDA synchronization, and fused kernel dispatch, let us implement a functional Python architecture prototype.
Step 1: Token-Splitting Tensor Decomposer
# tokenweave_decomposer.py
import torch
from typing import Tuple, List
class TokenWeaveDecomposer:
"""
Decomposes incoming sequence tensors into balanced token chunks
to enable asynchronous compute-communication pipelining.
"""
def __init__(self, min_split_tokens: int = 1024):
self.min_split_tokens = min_split_tokens
def split_sequence(self, x: torch.Tensor) -> Tuple[torch.Tensor, torch.Tensor, bool]:
"""
Splits activation tensor x of shape [batch, seq_len, hidden_dim]
along the sequence dimension into T_1 and T_2.
"""
batch_size, seq_len, hidden_dim = x.shape
total_tokens = batch_size * seq_len
# Only split if sequence length meets the minimum threshold
if total_tokens < self.min_split_tokens:
return x, None, False
mid_idx = seq_len // 2
chunk_1 = x[:, :mid_idx, :].contiguous()
chunk_2 = x[:, mid_idx:, :].contiguous()
return chunk_1, chunk_2, True Step 2: Fused AllReduce–RMSNorm Simulation Kernel
# tokenweave_fused_kernel.py
import torch
import torch.nn as nn
import time
from typing import Optional
class FusedAllReduceRMSNorm(nn.Module):
"""
Simulates the TokenWeave fused AllReduce-RMSNorm kernel.
In production, this is implemented as an optimized CUDA/NVSHARP kernel
consuming only 2-8 SMs and bypassing global memory round-trips.
"""
def __init__(self, hidden_dim: int, eps: float = 1e-6, num_gpus: int = 8):
super().__init__()
self.hidden_dim = hidden_dim
self.eps = eps
self.num_gpus = num_gpus
self.weight = nn.Parameter(torch.ones(hidden_dim))
def forward(self, partial_tensor: torch.Tensor, comm_stream: Optional[torch.cuda.Stream] = None) -> torch.Tensor:
"""
Simulates in-register reduction followed immediately by RMSNorm.
"""
# In actual deployment, NVLink hardware multicast sums partial_tensor across GPUs
# Simulated reduction across num_gpus
reduced_tensor = partial_tensor * self.num_gpus # Mock All-Reduce
# In-register RMSNorm computation (Zero HBM round-trip)
variance = reduced_tensor.pow(2).mean(dim=-1, keepdim=True)
normed_tensor = reduced_tensor * torch.rsqrt(variance + self.eps)
output = normed_tensor * self.weight
return output Step 3: Multi-Stream Pipelined Layer Orchestrator
# tokenweave_layer.py
import torch
import torch.nn as nn
import time
from typing import Dict, Any
from tokenweave_decomposer import TokenWeaveDecomposer
from tokenweave_fused_kernel import FusedAllReduceRMSNorm
class TokenWeaveTransformerBlock(nn.Module):
"""
Tensor-parallel transformer layer implementing TokenWeave compute-communication overlap.
"""
def __init__(self, hidden_dim: int, num_gpus: int = 8):
super().__init__()
self.hidden_dim = hidden_dim
self.num_gpus = num_gpus
self.decomposer = TokenWeaveDecomposer(min_split_tokens=1024)
# Column-parallel and row-parallel linear projections
self.mlp_gate = nn.Linear(hidden_dim, (hidden_dim * 4) // num_gpus, bias=False)
self.mlp_down = nn.Linear((hidden_dim * 4) // num_gpus, hidden_dim, bias=False)
# Fused AllReduce-RMSNorm kernel
self.fused_ar_norm = FusedAllReduceRMSNorm(hidden_dim, num_gpus=num_gpus)
# Multi-stream CUDA handles
self.compute_stream = torch.cuda.Stream() if torch.cuda.is_available() else None
self.comm_stream = torch.cuda.Stream() if torch.cuda.is_available() else None
def forward_overlapped(self, x: torch.Tensor) -> Tuple[torch.Tensor, Dict[str, float]]:
start_time = time.perf_counter()
t1, t2, is_split = self.decomposer.split_sequence(x)
if not is_split:
# Baseline execution if sequence is too small to split
h = self.mlp_down(torch.relu(self.mlp_gate(x)))
out = self.fused_ar_norm(h)
elapsed_ms = (time.perf_counter() - start_time) * 1000.0
return out, {"elapsed_ms": elapsed_ms, "overlap": False}
# Step 1: Compute GEMM on Chunk T1
h1 = self.mlp_down(torch.relu(self.mlp_gate(t1)))
# Step 2: Concurrent Overlap
# Stream B executes Fused AllReduce-RMSNorm on T1
# Concurrently, Stream A executes GEMM on Chunk T2
# (In CUDA, synchronized via torch.cuda.Event)
h2 = self.mlp_down(torch.relu(self.mlp_gate(t2))) # Stream A: Compute
out1 = self.fused_ar_norm(h1, self.comm_stream) # Stream B: Comm + Norm (Overlapped!)
# Step 3: Fused AllReduce-RMSNorm on Chunk T2
out2 = self.fused_ar_norm(h2, self.comm_stream)
# Concatenate normalized token slices
final_output = torch.cat([out1, out2], dim=1)
elapsed_ms = (time.perf_counter() - start_time) * 1000.0
return final_output, {
"elapsed_ms": elapsed_ms,
"overlap": True,
"tokens_chunk_1": t1.shape[1],
"tokens_chunk_2": t2.shape[1]
} Empirical Benchmarks: Evaluating TokenWeave
The researchers from Microsoft Research India evaluated TokenWeave on an industry-standard 8x NVIDIA H100 DGX system (80GB SXM5, 900 GB/s NVLink 4) across diverse frontier models:
- LLaMA-3.3-70B
- LLaMA-3-8B
- Mixtral-8x7B (MoE Architecture)
The evaluation compared TokenWeave against state-of-the-art inference baselines:
- vLLM-Multimem: An optimized baseline using NVIDIA’s Multimem hardware All-Reduce and NVSHARP support.
- TileLink: State-of-the-art GEMM-communication overlap engine.
- vLLM-nocomm (Counterfactual Upper Bound): A theoretical, unachievable ceiling where all inter-GPU network communication latency is set to zero.
| Model & Workload | Baseline (vLLM-Multimem) | TileLink Overlap | TokenWeave (MLSys 2026) | Theoretical Ceiling (vLLM-nocomm) |
|---|---|---|---|---|
| LLaMA-3.3-70B (1K Tokens) | 1.0x (Baseline) | 1.04x | 1.20x Speedup | 1.25x |
| LLaMA-3.3-70B (4K Tokens) | 1.0x (Baseline) | 1.09x | 1.28x Speedup | 1.26x (Beaten by TokenWeave!) |
| LLaMA-3.3-70B (8K Tokens) | 1.0x (Baseline) | 1.12x | 1.27x Speedup | 1.26x (Beaten by TokenWeave!) |
| LLaMA-3-8B (TP=4, 2K Tokens) | 1.0x (Baseline) | 1.03x | 1.22x Speedup | 1.24x |
| Communication SMs Required | 24 SMs (NCCL) | 16 SMs | 2 to 8 SMs (NVSHARP) | 0 SMs |
| Global Memory Round-Trips | 3x (HBM Write/Read) | 3x (HBM Write/Read) | 1x (In-Register Fused) | 2x |
| Serving Throughput (Tokens/s) | 1.0x (Baseline) | 1.06x | 1.19x Higher Throughput | 1.21x |
Critical Empirical Discoveries
- Beating the “Zero-Communication” Ceiling: At sequence lengths $\ge 4\text{K}$ tokens, TokenWeave actually outperforms
vLLM-nocomm(1.28x speedup vs. 1.26x theoretical ceiling)! This astonishing result occurs because TokenWeave does not merely hide communication latency behind compute—its fused AllReduce–RMSNorm kernel eliminates an entire global memory round-trip, delivering compute efficiency gains that exceed the cost of communication itself. - Overlap at 1,024 Tokens: Prior systems required massive 16k+ sequences to observe any meaningful overlap benefit. TokenWeave provides a 1.20x speedup at just 1,024 tokens, bringing the benefits of tensor-parallel overlap into standard enterprise conversational workloads.
- Elimination of SM Contention: By leveraging hardware multicast to drop the communication SM footprint from 24 SMs down to just 2 to 8 SMs, matrix multiplication kernels maintain full occupancy across 95%+ of the GPU’s tensor cores.
Integrating TokenWeave with AIFetchly Infrastructure
In distributed enterprise AI ecosystems, high-throughput model serving powers complex automated data lifecycles:
- High-Throughput Web Intelligence & Document Extraction: Enterprise pipelines extracting multi-page documents via automated web scraping stream thousands of tokens into distributed inference servers for entity extraction and summarization. Deploying TokenWeave accelerates tensor-parallel prefill latency by up to 1.28x, drastically reducing pipeline completion times.
- Low-Latency API Integrations: When delivering real-time responses through custom API integrations and live data fetching, cutting 20% to 28% of model latency allows enterprise applications to comfortably satisfy strict sub-second response contracts.
- Infrastructure Cost Reduction: Achieving 19% higher serving throughput on the same physical GPU hardware directly improves cloud economics. Enterprise clusters running 70B or 405B parameter models can serve significantly more concurrent users without leasing additional 8x H100 DGX nodes. Explore our transparent pricing tiers and consult our developer documentation to discover how the AIFetchly platform unifies data harvesting, vector search, and state-of-the-art LLM inference into a scalable enterprise stack.
Future Horizons: The Evolution of Tensor-Parallel Acceleration
TokenWeave establishes a new design pattern for distributed AI silicon:
- Compiler-Automated Kernel Fusion: Future deep learning compilers (such as TorchInductor and Triton) will automatically fuse collective communication primitives with downstream elementwise operations (such as SwiGLU, GELU, and residual additions).
- Scale-Out Overlap with Ultra-Ethernet: Expanding TokenWeave’s minimal-SM architecture across emerging Ultra Ethernet Consortium (UEC) standards will bring near-NVLink overlap efficiencies to multi-node clusters.
- Microsecond Multi-Token Pipelining: Splitting sequences into $N > 2$ sub-token chunks will enable continuous, fine-grained wave pipelining across ultra-deep transformer architectures like 405B+ parameter frontiers.
Key Technical Takeaways
- The Communication Overhead Dilemma: Synchronous All-Reduce collectives consume up to 45% of forward layer latency in tensor-parallel LLM serving.
- Token-Splitting Enables Early Overlap: Dividing sequences into balanced chunks unlocks compute-communication overlap for sequence lengths as small as 1,024 tokens.
- Fused AllReduce–RMSNorm Kernel: Fusing network reduction directly with variance normalization in registers slashes global memory traffic by 66% and eliminates redundant HBM round-trips.
- Minimal SM Contention via NVSHARP: Using hardware multicast reduces the communication SM footprint to just 2 to 8 SMs, leaving 95%+ of GPU resources free for tensor GEMMs and boosting serving throughput by 1.19x.