Azul Systems

OpenJDK-based Java performance solutions for enterprises

Compiler Performance Engineer

Systems Software EngineeringConfirmed live in the last 24 hours

Full-timeNo salary listedHybrid

About the Job

Requirements

At least 2 years of professional experience in compilers, JIT compilers, or low-level performance engineering.
Strong C++ design and coding skills.
A solid understanding of compiler optimization theory, including static single assignment (SSA), data-flow analysis, and loop transformations.
Ability to read assembly and reason about why one instruction sequence is faster than another.

Responsibilities

Analyze Java benchmarks and customer workloads, identify gaps in generated code, and trace them to their root cause in the compiler.
Implement and improve optimizations in Falcon's middle end and back end, including inlining, loop optimizations, vectorization, redundancy elimination, speculative optimizations, and their interaction with the runtime.
Improve code generation for x86_64 and AArch64.
Write tests and benchmarks that demonstrate improvements and protect against regressions.
Contribute changes upstream to LLVM where appropriate.

Desired Qualifications

Experience with LLVM IR and LLVM optimization passes, or with another optimizing compiler such as HotSpot C2, Graal, GCC, or V8.
Experience with profilers such as perf, VTune, or async profiler.
Knowledge of x86_64 and/or AArch64 microarchitecture.
Experience with Java, Scala, Kotlin, or JVM internals.
MSc or PhD in Computer Science with a compiler or performance focus.

Falcon is the optimizing just in time (JIT) compiler in Azul Platform Prime. It compiles hot Java bytecode into highly optimized machine code and delivers Java performance that standard JVMs do not reach. Falcon is built on LLVM.

We are looking for a Compiler Performance Engineer to make Falcon generate even faster code. This is not a compiler front end role and not a compiler built from scratch: the compiler exists, runs in production at large enterprises, and your job is to find where the generated code is slower than it should be and fix it in the optimizer and code generator.

You will join a distributed team of compiler experts and work on real workloads with direct, measurable impact on customer performance.

What You Will Do (aka Responsibilities)

Analyze performance of Java benchmarks and customer workloads, find gaps in generated code and trace them to their root cause in the compiler

Implement and improve optimizations in Falcon's middle end and back end: inlining, loop optimizations, vectorization, redundancy elimination, speculative optimizations and their interaction with the runtime

Improve code generation for x86_64 and AArch64

Write tests and benchmarks that prove the improvement and protect it from regressions

Contribute changes upstream to LLVM where it makes sense

What You'll Bring (Experience, Skills)

2+ years of professional experience in compilers, JIT compilers or low level performance engineering

Strong C++ design and coding skills

Solid understanding of compiler optimization theory: SSA, data flow analysis, loop transformations

Ability to read assembly and reason about why one instruction sequence is faster than another

Very Nice to Have

Experience with LLVM IR and LLVM optimization passes, or with another optimizing compiler such as HotSpot C2, Graal, GCC or V8

Experience with profilers such as perf, VTune or async profiler

Knowledge of x86_64 and/or AArch64 microarchitecture

Experience with Java, Scala or Kotlin, or with JVM internals

MSc or PhD in Computer Science with a compiler or performance focus

About the Company

Azul Systems

OpenJDK-based Java performance solutions for enterprises

Azul Systems provides enterprise OpenJDK-based Java solutions designed to boost performance and security for cloud applications. Its product offerings include a Java platform licensed to customers, 24/7 support, and migration services that help organizations move from Oracle JDK to Azul with minimal downtime. Azul’s platform integrates with existing Java technologies and supports IoT and big data workloads, delivering low-latency, stable applications across millions of installations. The company differentiates itself by focusing on open Java implementation for enterprises, serving many Fortune 100 companies, and employing highly experienced Java engineers to ensure reliable operation and expert guidance. Azul’s goal is to help businesses run faster, more secure Java in the cloud, with easy migration, strong support, and scalable performance across diverse workloads.

Company size: 501-1,000
Company stage: Series F
Total funding: $177.7M
Headquarters: Sunnyvale, CA
Founded: 2002

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