Doubleword
Notes on building AI systems
- Posts
- 63 from 28 May 2025 to 22 Sep 2026
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- weekly (46 in the last year)
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- company blog
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2026 40
- Unlocking parallel test-time scaling for long-horizon agents
- What is a Megawatt Worth?
- What happens when a GPU writes memory
- What happens when a GPU reads memory
- On-the-fly snapshot compression for elastic inference at scale
- The case for disaggregated LLM serving
- Gigatoken: making tokenisation care about the hardware
- You Could Have Come Up With Kimi Delta Attention
- Throughputmaxxing: DeepSeek-V4-Flash on Isambard-AI
- NVLink, NVSwitch, and all that
- Reverse-engineering NVIDIA's cuda-checkpoint for faster cold starts
- Width vs. depth: speculating on the margin
- The swarm that designs itself
- What happens when you run a CUDA kernel
- Prediction: A Frontier Open Source LLM Will Be Released On 3rd December 2026
- Anatomy of a Diffusion Language Model
- FlashOffload: 7x Cheaper Prefills with Offloading
- Adaptive speculative decoding: picking draft lengths at runtime
- InfiniBand, RoCE, and all that
- UCCL-EP: An expert parallel communications kernel without owning the NIC
- Anatomy of a high-performance EP kernel
- The economics of speculative decoding
- Bringing up DeepSeek-V4-Flash on AMD MI300X
- Pushing memory bound kernels beyond the speed of light with lossless decompression
- Inference when no one is waiting
- MoE expert co-activations: Reordering inputs yields easy throughput gains.
- Speculative KV coding: losslessly compressing KV cache by up to ~4× using a predictor model
- Tensor Network Attention
- In search of wasted bits: how much information do LLM weights carry?
- tANS: precomputing rANS
- Also-rANS: Asymmetric Numeral Systems for entropy coding
- Cloudburst: 70x faster cold(ish) starts for SGLang
- OCR and the Bitter Lesson
- Weighted random fallback flattens to uniform under high error rates
- QueueSpec: Drafting While You Wait
- Price Reduction for Qwen3-235B on Doubleword
- Scaling Curation with LLM Comparisons
- LLM powered data structures: A lock-free binary search tree
- ZeroDP: Just-In-Time Weight Offloading over NVLink for Data Parallelism
- Large-Scale Semantic Search Without Embeddings
2025 23
- Parallel Primitives for Multi-Agent Workflows
- $1 for a Year of Research Digests. That's Less Than a Coffee.
- Why Batch Inference Matters: Moving from AI Assistants to Autonomous Agents
- Behind the Stack, Ep 13: Faster Inference: Speculative Decoding for Batched Workloads
- Behind the Stack, Ep 12: Understanding Model Parallelism
- Behind the Stack, Ep 11: How Speculative Decoding Speeds Up Language Models
- Benchmarking the Doubleword Control Layer
- Chasing Cheap Tokens: 2x Cheaper Tokens Than H100s with Consumer Cards
- Choosing the Right Model for the Use Case
- Understanding Chargeback in the Context of Self-Hosted Systems
- LLM guided scheduling | Doubleword
- Scheduling in inference engines | Doubleword
- Should GPUs make Free Trade Agreements? | Doubleword
- Behind the Stack, Ep 10: Batched Endpoints | Doubleword
- Behind the Stack, Ep 9: How to Evaluate Open Source LLMs | Doubleword
- Behind the Stack, Ep 8: Choosing the Right Inference Engine for Your LLM Deployment | Doubleword
- Behind the Stack, Ep 7: Choosing the Right Quantization for Self-Hosted LLMs | Doubleword
- Behind the Stack, Ep 6: How to Speed up the Inference of AI Agents | Doubleword
- Behind the Stack, Ep 5: Making RAG Work for Multimodal Documents | Doubleword
- Behind the Stack, Ep 4: Making Your Load Balancer LLM-Aware | Doubleword
- Behind the Stack, Ep 3: How to Serve 100 Models on a Single GPU with No Cold Starts | Doubleword
- Behind the Stack, Ep 2: How Many Users Can My GPU Serve? | Doubleword
- Behind the Stack, Ep 1: What Should I Be Observing in my LLM Stack? | Doubleword