Performance Engineer, Kernel and Memory

Cloudflare; United States; On-site; USD 180,000 - 240,000; Full time

Job summary

United States Digital Space LLC is seeking an expert Linux kernel memory-management engineer to help optimize memory usage at scale. You will work on the kernel memory subsystem, address bottlenecks, and contribute changes upstream.

The role collaborates across kernel, networking, storage, and product teams to implement high-impact MM improvements, with a focus on performance, scalability, and cost efficiency as demand grows.

Qualifications

• Deep expertise in the Linux kernel memory-management subsystem.
• Track record of upstream Linux contribution.
• Strong systems programming in C.
• Ability to own a problem and drive outcomes.

Responsibilities

• Diagnose and fix performance and scalability bottlenecks in the Linux kernel memory-management subsystem, informed by real production telemetry.
• Land your work upstream. We expect MM changes to go to mainline first and want you to keep doing the maintainership and review work that earns standing in the community.
• Build and extend low-overhead kernel instrumentation (tracepoints, BPF, perf) so we keep measuring before we change, and prove the impact afterwards.
• Partner with kernel, networking, storage, and product engineers across the company to turn observed system behavior into concrete MM improvements.
• Set technical direction for how the company uses, tunes, and evolves kernel memory management as we push utilization higher.

Skills

Linux kernel memory management

C programming

Upstream Linux contribution

Systems performance analysis

Tools

BPF

Perf tooling

Kernel tracing

Job description

About Us

At the company, we are on a mission to help build a better Internet. Today the company runs one of the world’s largest networks that powers millions of websites and other Internet properties for customers ranging from individual bloggers to SMBs to Fortune 500 companies. the company protects and accelerates any Internet application online without adding hardware, installing software, or changing a line of code. Internet properties powered by the company all have web traffic routed through its intelligent global network, which gets smarter with every request. As a result, they see significant improvement in performance and a decrease in spam and other attacks. the company was named to Entrepreneur Magazine’s Top Company Cultures list and ranked among the World’s Most Innovative Companies by Fast Company.

At the company, we’re not looking for people who wait for a polished roadmap; we’re looking for the builders who see the cracks in the Internet that everyone else has simply learned to live with. We value candidates who have the instinct to spot a "normalized" problem and the AI-native curiosity to create a solution using the latest tools. Our culture is built on iteration, leveraging AI to ship faster today to make it better tomorrow, while ensuring that every improvement, no matter how small, is shared across the team to lift everyone up. If you’re the type of person who values curiosity over bureaucracy, and that AI is a partner in solving tough problems to keep the Internet moving forward, you’ll fit right in.

Available Locations

• Austin, US

• New York, NY

• Washington DC

About the Role

At the company, we have our eyes set on an ambitious goal: to help build a better Internet. Today the company runs one of the world’s largest networks that powers approximately 25 million Internet properties, for customers ranging from individual bloggers to SMBs to Fortune 500 companies. the company protects and accelerates any Internet application online without adding hardware, installing software, or changing a line of code. Internet properties powered by the company all have web traffic routed through its intelligent global network, which gets smarter with every request. As a result, they see significant improvement in performance and a decrease in spam and other attacks. the company was named to Entrepreneur Magazine’s Top Company Cultures list and ranked among the World’s Most Innovative Companies by Fast Company.

We realize people do not fit into neat boxes. We are looking for curious and empathetic individuals who are committed to developing themselves and learning new skills, and we are ready to help you do that. We cannot complete our mission without building a diverse and inclusive team. We hire the best people based on an evaluation of their potential and support them throughout their time at the company. Come join us!

About the Department

the company’s engineering teams build and maintain the systems and products that power our global platform. A global platform which is within approximately 50 milliseconds of about 95% of the Internet connected population, serving on average, over 46 million HTTP requests per second.

About the Team

Delivering this platform with high performance and efficiency depends on advanced Linux kernel and hardware capabilities, and that is where this team works.

The problem you would own

Using memory efficiently is one of the highest-leverage problems we have. At our scale, how the kernel's memory-management subsystem behaves under pressure has direct consequences for both performance and cost. As DRAM prices climb, getting more out of the memory we already own is a real lever on infrastructure spend.

Using custom low-overhead instrumentation on production servers, we have identified several scalability bottlenecks in the kernel memory layer that show up under real workloads. We are looking for an expert to take on these problems, fix them against production workloads, and drive the changes upstream. Solving them lifts efficiency and latency across the entire fleet rather than in one

Place.

What you will do

• Diagnose and fix performance and scalability bottlenecks in the Linux kernel memory-management subsystem, informed by real production telemetry at a scale few environments can offer.

• Land your work upstream. We expect MM changes to go to mainline first and want you to keep doing the maintainership and review work that earns standing in the community.

• Build and extend low-overhead kernel instrumentation (tracepoints, BPF, perf) so we keep measuring before we change, and prove the impact afterwards.

• Partner with kernel, networking, storage, and product engineers across the company to turn observed system behavior into concrete MM improvements.

• Set technical direction for how the company uses, tunes, and evolves kernel memory management as we push utilization higher.

Requirements

• Deep expertise in the Linux kernel memory-management subsystem: the page allocator, virtual memory and memory mapping, reclaim, and the locking and concurrency that hold it together.

• A track record of upstream Linux contribution, ideally including maintainership or sustained work in MM or an adjacent subsystem.

• Strong systems programming in C, with the judgement to make high-risk changes to shared infrastructure safely.

• Ability to dive deep into a complex codebase while keeping the fleet-wide picture in mind, and to own a problem and its outcome rather than a single patch.

• Clear communication with engineers across many teams, since the symptoms of an MM problem usually show up far from the MM code.

Bonuses

• Strong understanding of Linux kernel internals pertaining to memory management

• Experience troubleshooting and resolving performance issues in large-scale distributed systems.

• Experience with large scale configuration/deployment management.

What Makes the company Special?

We’re not just a highly ambitious, large-scale technology company. We’re a highly ambitious, large-scale technology company with a soul. Fundamental to our mission to help build a better Internet is protecting the free and open Internet.

Project Galileo

Since 2014, we've equipped more than 2,400 journalism and civil society organizations in 111 countries with powerful tools to defend themselves against attacks that would otherwise censor their work, technology already used by the company’s enterprise customers--at no cost.

Athenian Project

In 2017, we created the Athenian Project to ensure that state and local governments have the highest level of protection