Learning AI Infrastructure Through Two Lenses AI Infrastructure 学习总览

AI Infra · Overview

AI Infra Learning Notes · Overview
From understanding how a technology runs to understanding why it exists, who needs it, and how it creates real value.

01 Why I Started

The reason was simple at first: I was interviewing with an AI infrastructure startup.

I read through the company's website, its GitHub, and its public technical material. I also looked at the team's backgrounds and open roles on LinkedIn. It turned out to be a field that sits deep in the technical stack.

Before anything else, I needed to understand the technical world it operates in. I also wanted to actually learn it: why these technologies exist, what problems they solve, and how they turn into real value.

So I built my own learning roadmap from scratch.

FIG. 01 · THE STARTING POINTAn opportunity → A learning system

Interview Opportunity

AI Infrastructure Startup

→

Explore Public Sources

Website · GitHub · LinkedIn · JDs

→

Build a Knowledge Tree

Structure before details

Before learning the answers, I needed to understand the questions.

02 How I Designed My Learning

I split my learning into two tracks that complement each other.

Track A: Understand the Technology. The first track closes my most direct knowledge gap. I want to understand what problems engineers are solving and why they make the technical decisions they do.

Track B: Understand the Users & Business. I enjoy technology. I also enjoy turning complex knowledge into something simple that other people can use. I've always been interested in user needs, user experience, and how products get adopted.

But good technology doesn't guarantee a valuable product.

As a user, I don't buy a product to admire the technology behind it. I buy it because it solves my problem, improves my experience, or creates some kind of value for me.

How, then, do we close the gap between technical capability and user value? That question is why Track B exists.

Track A helps me understand what the technology can do. Track B helps me understand who needs it, why they need it, and how to get it used.

FIG. 02 · TWO LENSES, ONE GOALTechnology × User value
TRACK A · TECHNICAL LENS

Understand
How It Works

How models, GPUs, and inference systems work, and the constraints and trade-offs behind engineering decisions.

  • Model computation
  • GPU and systems
  • Serving and optimization
TRACK B · PRODUCT LENS

Understand
Why It Matters

Developers' real problems, user experience, product choices, and business value.

  • User problems & evidence
  • Product value & experience
  • Adoption and business
Product Judgment
Bridge the gap between technical capability and real user needs
The two tracks aren't two separate course lists. They look at the same question from different angles: how does a technology create real value?

How I Study

I start by using AI to collect and organize public material: project docs, GitHub, company websites, technical write-ups, and job postings. I add what I've seen of the team's backgrounds and use all of it to understand the basic structure of the field.

Next, I ask the AI to build a knowledge tree. I check how the modules connect and revise the structure until it holds together. Only then do I go deep on each module, one at a time.

For each topic, I start with the what, the why, and the how. Then I test my understanding against concrete scenarios and questions. I also write my misunderstandings, my corrections, and new ideas into these notes.

01

Explore Sources

Public material and product information

02

Build the Tree

Settle the full structure first

03

What / Why / How

Understand each mechanism

04

Feynman Check

Explain it in my own words

05

Document & Reflect

Record corrections and new ideas

03 My Learning Map

I wanted each module to be a question worth answering, not just a term. The map moves from a single computation to a full system, then from technical capability to user value.

Track A — Technology

It starts with a single LLM computation, then moves to the resource limits of GPUs. From there it covers LLM serving for many users, inference engines, and post-training. That is the technology line. Turning an open-source project into a business sits in Track B, not here.

TRACK A · Understand the Technology TRACK A · Understand the Technology One computation → GPUs → serving many users → inference engines → post-training AI Infrastructure Make models run, scale, and improve One Computation Model + hardware Serving Many Users Systems + engines Improving Models Training loop 01 · LLM Fundamentals What computation happens when a prompt enters an LLM? Parameters · Tokens · Forward Pass · Prefill · Decode · KV Cache Read note → 02 · GPU & Hardware Why can powerful GPUs still slow LLM inference down? GPU Memory · HBM · Compute · Bandwidth · Latency · Throughput Read note → 03 · LLM Serving Systems How does one model serve thousands of users at once? Scheduling · Batching · Caching · Concurrency · Engine Read note → 04 · SGLang & Inference Optimization What trade-offs do open-source inference engines make? Prefix Caching · Continuous Batching · PD Disaggregation · SGLang Read note → 05 · Post-training & Reinforcement Learning Why does improving AI agents take training infrastructure? Post-training · RL · Rollouts · Rewards · Train–Serve Loop
Each question in the tree is that module's learning goal. Modules with a published note link straight to it. The rest show the learning question and key concepts.

Track B — Product & Business

It starts with the market and real developer problems, then asks how a technical capability becomes product value. Adoption and building a business are one phase: developer experience, go-to-market, and how an open-source project gets used and paid for. It ends with work you can actually contribute.

TRACK B · Understand Users & Business TRACK B · Understand Users & Business Landscape → developer problems → product value → adoption → contribution Product & Business Turn technical capability into real user value Market & Users Landscape + evidence Evaluate Value Capability → outcome Drive Adoption & Build a Business GTM · open source · revenue Contribute in Practice Evidence + execution 01 · Mapping the AI Infra Ecosystem Who builds, uses, and pays for AI infrastructure? Value Chain · Model Providers · Managed Inference · Buyers · Business Models Read note → 02 · Developer Research & Customer Discovery What problems do developers actually encounter? GitHub Issues · PRs · Docs · Slack · JTBD · User Evidence 03 · From Technical Capability to Product Value Who benefits from optimization, and how do we verify its value? Real Workloads · Trade-offs · Use Cases · Differentiation · Validation 04 · Drive Adoption & Build a Business How does a product get adopted, and how does an open-source project become a business? DX · PMM · DevRel · GTM · Open-source business · Monetization 05 · Real-World Contribution & Portfolio What useful work can I actually contribute? Documentation PRs · Technical Explainers · Workshops · Growth Experiments
The tree starts from market and user evidence and moves step by step toward product judgment, developer adoption, and real contribution. Building a business lives in this track, next to adoption, not as a sixth technology module.

04 What I've Learned So Far

01 From One AI User to Inference at Scale

I used to understand AI mostly as an everyday user: send a request, then wait for the model's answer.

Now I can see the other side. When many requests hit the system at once, the question isn't just whether the model can produce an answer. It's also how GPU resources get allocated, how requests get scheduled, which computation can be reused, and how to balance cost, latency, and throughput.

For the first time, I started to understand what infrastructure it takes to run AI applications at scale.

FIG. 04A · INFERENCE AT SCALESame model, a different systems problem

One Request

LLM InferenceOne input → one response
One user sees a model answer

Many Concurrent Requests

Scheduling · Batching · CachingRequests compete for shared resources
GPU / Memory / ComputeManage latency, throughput & cost
The model is the same in both cases. What changes at scale is that many requests compete for the same GPU memory and compute.

02 Higher Metrics Aren't Always Better

A higher cache hit rate, for example, doesn't necessarily mean lower end-to-end latency. It says even less about developer experience.

Caching takes up resources, and requests may have to wait. Improving one technical metric doesn't guarantee that the whole system, or the user experience, gets better.

Before optimizing anything, I should understand the real workload and what users actually care about. Only then can I decide which metrics to optimize and how to measure the result.

FIG. 04B · OPTIMIZATION IS A TRADE-OFFOne metric ↑ does not mean every outcome ↑
An Optimization Decision: Keep More Reusable KV Cache

Cache Reuse ↑

May cut repeated prefill computation

Memory Pressure ↑

May take GPU memory that other requests need

↓
End-to-End Latency & Developer Experience = ?Depends on the real workload, resource contention, scheduling, and overall system behavior
A conceptual sketch of the trade-off, not experimental results from any specific system. Whether an optimization works has to be checked against real usage.

05 Reflections & Open Questions

I used to focus on consumer products and the experience of everyday users.

AI infrastructure introduced me to completely different perspectives: developers, infrastructure teams, enterprises, and people building complex agent systems.

I've really enjoyed the process. It feels like exploring a map. At first you only know the small area where you live, and it's hard to picture what lies beyond it. Once you start walking outward, you find how many different problems, technologies, and ways of working are out there.

And the more I learn, the more I see how much I still don't know.

FIG. 05 · OPENING UP THE MAPAn expanding view of the AI world
THE FAMILIARConsumer AIindividual users A BiggerMap DevelopersInfrastructure TeamsAgent BuildersEnterprises A new world of questions
The consumer AI I knew is just one region on the map. Learning infrastructure showed me the larger world of technology and users behind it.

Next, I want to connect what I understand about the technology to real developer research instead of keeping it theoretical.

The questions I most want to explore next:

  1. When developers choose an AI infrastructure product, what do they weigh besides performance and cost?
  2. How can we tell whether a technical optimization actually improves the user experience?
  3. What does a strong open-source project need to become a widely adopted, sustainable product?

I hope this roadmap helps me understand a new industry. I also hope it helps me find the value I can create where technology, users, and business meet.

AI Infra 学习笔记 · 总览
从理解一项技术如何运行,到理解它为什么存在、谁需要它,以及如何真正创造价值。

01 Why I Started

最初的原因其实很简单:我在面试一家 AI Infrastructure Startup。

我开始浏览公司的官网、GitHub、公开技术资料,也去 LinkedIn 看团队的背景和招聘岗位。这个领域其实深入技术底层。

那么我首先需要理解它所处的技术世界。而且我希望真正可以学习到,能够理解这些技术为什么存在、解决什么问题,以及它们如何转化成实际价值。

于是,我从零做了一套自己的 Learning Roadmap。

FIG. 01 · THE STARTING POINTAn opportunity → A learning system

Interview Opportunity

AI Infrastructure Startup

→

Explore Public Sources

Website · GitHub · LinkedIn · JDs

→

Build a Knowledge Tree

Structure before details

Before learning the answers, I needed to understand the questions.

02 How I Designed My Learning

我把整个学习过程分成了两条相互补充的路线。

Track A — Understand the Technology. 第一条路线解决的是我最直接的知识缺口。我的目标是希望理解工程师在解决什么问题,以及这些技术决策背后的原因。

Track B — Understand the Users & Business. 我喜欢技术,也喜欢把复杂的知识转化成简单易懂、别人能够使用的东西。我一直对用户需求、用户体验和产品如何被采用很感兴趣。

但技术做得好,不代表产品一定有价值。

从用户的角度来说,我购买一个产品,不是为了欣赏它背后有多先进的技术,而是因为它能够解决我的问题、改善我的体验,或者为我创造某种价值。

那么,技术能力和用户价值之间的 Gap,究竟应该如何弥合?这就是 Track B 存在的原因。

Track A 帮助我理解技术能做什么;Track B 帮助我理解谁需要它、为什么需要,以及如何让它真正被使用。

FIG. 02 · TWO LENSES, ONE GOALTechnology × User value
TRACK A · TECHNICAL LENS

Understand
How It Works

理解模型、GPU 与推理系统的运行机制,理解工程决策背后的约束和取舍。

  • Model computation
  • GPU and systems
  • Serving and optimization
TRACK B · PRODUCT LENS

Understand
Why It Matters

理解开发者的真实问题、用户体验、产品选择与商业价值。

  • User problems & evidence
  • Product value & experience
  • Adoption and business
Product Judgment
Bridge the gap between technical capability and real user needs
两条路线不是两个独立的课程清单,而是从不同角度理解同一个问题:一项技术怎样才能创造真实价值?

我是怎么学习的?

我先用 AI 帮助收集和组织公开资料,包括项目文档、GitHub、官网、相关技术介绍和招聘信息,再结合自己观察到的团队背景,理解这个领域的基本结构。

我会先要求它建立一棵 Knowledge Tree,检查各个模块之间的逻辑关系,反复调整,直到我认为整个结构合理,再逐个深入。

学习过程中,我会先理解 What、Why 和 How,再通过具体场景和提问检验自己的理解。我也会把自己的误解、修正过程和新的思考整理进这些笔记。

01

Explore Sources

公开资料与产品信息

02

Build the Tree

先确定完整结构

03

What / Why / How

理解每一个机制

04

Feynman Check

用自己的话解释

05

Document & Reflect

记录修正与思考

03 My Learning Map

我想让每个 Module 不只是一个术语,而是一个值得回答的问题。从微观计算到完整系统,再从技术能力走向用户价值。

Track A — Technology

从单次 LLM 计算开始,逐渐理解 GPU 的资源限制,再进入多用户环境下的 LLM Serving、推理引擎和 Post-training。技术线到这里就完整了。开源项目怎么变成一门生意,放在 Track B,不放在这里。

TRACK A · Understand the Technology TRACK A · Understand the Technology One computation → GPUs → serving many users → inference engines → post-training AI Infrastructure Make models run, scale, and improve One Computation Model + hardware Serving Many Users Systems + engines Improving Models Training loop 01 · LLM Fundamentals What computation happens when a prompt enters an LLM? Parameters · Tokens · Forward Pass · Prefill · Decode · KV Cache 阅读笔记 → 02 · GPU & Hardware Why can powerful GPUs still slow LLM inference down? GPU Memory · HBM · Compute · Bandwidth · Latency · Throughput 阅读笔记 → 03 · LLM Serving Systems How does one model serve thousands of users at once? Scheduling · Batching · Caching · Concurrency · Engine 阅读笔记 → 04 · SGLang & Inference Optimization What trade-offs do open-source inference engines make? Prefix Caching · Continuous Batching · PD Disaggregation · SGLang 阅读笔记 → 05 · Post-training & Reinforcement Learning Why does improving AI agents take training infrastructure? Post-training · RL · Rollouts · Rewards · Train–Serve Loop
树中的问题是每个模块的学习目标。已提供原文地址的模块标题可直接打开对应笔记;其他模块保留学习问题与知识点。

Track B — Product & Business

从市场和真实的开发者问题开始,再看一项技术能力怎么变成产品价值。采用和做成一门生意是同一个阶段:开发者体验、GTM,以及开源项目怎么被用起来、怎么收费。最后落到你真正能做出来的贡献。

TRACK B · Understand Users & Business TRACK B · Understand Users & Business Landscape → developer problems → product value → adoption → contribution Product & Business Turn technical capability into real user value Market & Users Landscape + evidence Evaluate Value Capability → outcome Drive Adoption & Build a Business GTM · open source · revenue Contribute in Practice Evidence + execution 01 · Mapping the AI Infra Ecosystem Who builds, uses, and pays for AI infrastructure? Value Chain · Model Providers · Managed Inference · Buyers · Business Models 阅读笔记 → 02 · Developer Research & Customer Discovery What problems do developers actually encounter? GitHub Issues · PRs · Docs · Slack · JTBD · User Evidence 03 · From Technical Capability to Product Value Who benefits from optimization, and how do we verify its value? Real Workloads · Trade-offs · Use Cases · Differentiation · Validation 04 · Drive Adoption & Build a Business How does a product get adopted, and how does an open-source project become a business? DX · PMM · DevRel · GTM · Open-source business · Monetization 05 · Real-World Contribution & Portfolio What useful work can I actually contribute? Documentation PRs · Technical Explainers · Workshops · Growth Experiments
从市场与用户证据出发,逐层走向产品判断、开发者采用和实际贡献。做成一门生意放在这条线里,跟采用放在一起,不再单列成技术线的第六块。

04 What I've Learned So Far

01 从单个 AI 用户到大规模推理系统

过去,我更多是从普通使用者的角度理解 AI:输入请求,然后等待模型返回结果。

现在,我可以看到另一面。当大量请求同时进入系统时,问题就不只是模型能不能生成答案,还包括 GPU 资源如何分配、请求怎样调度、哪些计算可以复用,以及如何在成本、延迟和吞吐量之间取舍。

这让我第一次去理解支撑 AI 应用规模化运行需要怎样的基础设施。

FIG. 04A · INFERENCE AT SCALESame model, a different systems problem

One Request

LLM InferenceOne input → one response
One user sees a model answer

Many Concurrent Requests

Scheduling · Batching · CachingRequests compete for shared resources
GPU / Memory / ComputeManage latency, throughput & cost
两种情况下模型是同一个。规模变大之后,变化的是大量请求在争抢同一块 GPU 的显存和算力。

02 技术指标不是越高越好

比如,更高的 Cache Hit Rate 并不一定意味着更低的 End-to-End Latency,更不一定意味着更好的 Developer Experience。

因为缓存需要占据资源,请求也可能需要等待。某一项技术指标改善,并不保证整个系统或用户体验都会改善。

所以,在优化之前,应该先理解真实的 Workload,明确用户真正关心什么,再决定要优化哪些指标,以及如何衡量结果。

FIG. 04B · OPTIMIZATION IS A TRADE-OFFOne metric ↑ does not mean every outcome ↑
An Optimization Decision: Keep More Reusable KV Cache

Cache Reuse ↑

可能减少重复 Prefill 的计算

Memory Pressure ↑

可能挤占其他请求所需的显存

↓
End-to-End Latency & Developer Experience = ?取决于真实 Workload、资源竞争、调度以及整体系统行为
这是概念性取舍示意,不是某个系统的实验结果;要判断优化是否成功,需要结合真实使用场景验证。

05 Reflections & Open Questions

过去,我更关注消费级产品和普通用户的体验。

AI Infrastructure 让我开始接触完全不同的视角:Developers、Infrastructure Teams、Enterprises,以及正在构建复杂 Agent 系统的人。

我很喜欢这个过程。它有点像探索一张地图。原本你只知道自己生活的那一小块区域,甚至很难想象地图之外还有什么。直到你开始往外走,才发现原来存在这么多不同的问题、技术和工作方式。

而且很有意思的是,学得越多,我越能意识到自己还有多少不了解。

FIG. 05 · OPENING UP THE MAPAn expanding view of the AI world
THE FAMILIARConsumer AIindividual users A BiggerMap DevelopersInfrastructure TeamsAgent BuildersEnterprises A new world of questions
原来熟悉的 Consumer AI 只是地图上的一片区域;学习 Infrastructure,让我看见背后更大的技术与用户世界。

现在,我希望把技术理解和真实的 Developer Research 连接起来,而不是停留在理论层面。

接下来我最想探索的问题包括:

  1. 开发者实际选择 AI Infrastructure 产品时,除了性能和成本,还会考虑什么?
  2. 我们如何判断某一项技术优化,是否真正改善了用户体验?
  3. 一个优秀的开源技术项目,需要什么才能发展成被广泛采用、可持续发展的产品?

我希望这条学习路线不仅帮助我理解一个新行业,也帮助我进一步探索自己能够在技术、用户和商业的交汇处创造什么价值。

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