Senior ML Performance Engineer

Lemurian Labs; Toronto; On-site; CAD 60,000 - 80,000; Full time

Job summary

A technology company focused on AI in Toronto seeks a Senior ML Performance Engineer to architect a performance testing platform. You will measure and optimize the performance of large language models on GPUs. The role requires extensive experience in performance engineering and knowledge of ML frameworks. Ideal candidates will have strong programming skills in Python and C/C++. Additional benefits include equity options, medical, and retirement savings plans.

Benefits

Equity

Company bonus opportunities

Medical benefits

Dental and vision benefits

Retirement savings plan

Supplemental wellness benefits

Qualifications

• 7+ years of experience in performance engineering or systems engineering roles.
• Deep understanding of ML inference workloads, particularly transformer-based models.
• Hands-on experience with GPU programming and optimization.

Responsibilities

• Design performance testing platform for evaluating LLM inference workloads.
• Define benchmarking methodology, metrics, and test suites.
• Establish baseline performance for unoptimized models.

Skills

Performance engineering

GPU programming

Python

C/C++

Machine Learning frameworks

Benchmarking

Tools

CUDA

ROCm

CI/CD systems

Docker

Job description

About Us

At Lemurian Labs, we’re on a mission to bring the power of AI to everyone—without leaving a massive environmental footprint. We care deeply about the impact AI has on our society and planet, and we’re building a solid foundation for its future, ensuring AI grows sustainably and responsibly. Innovation should help the world, not harm it.

We are building a high-performance, portable compiler that lets developers "build once, deploy anywhere." Yes, anywhere. We’re talking about seamless cross-platform compatibility, so you can train your models in the cloud, deploy them to the edge, and everything in between—all while optimizing for resource efficiency and scalability.

If the idea of sustainably scaling AI motivates you and you’re excited about making AI development both powerful and accessible, then we’d love to have you. Join us at Lemurian Labs, where you can have fun building the future—without leaving a mess behind.

The Role

We’re looking for a Senior ML Performance Engineer to architect and lead our Performance Testing Platform from the ground up. You’ll be the technical authority on how we measure, validate, and optimize the performance of large language models (Llama 3.2 70B, DeepSeek, and others) before and after compiler optimization on modern GPU architectures.

This is a high-impact role where you’ll directly influence our product quality and our customers' success. You’ll work at the intersection of ML systems, GPU architecture, and performance engineering—building the infrastructure that proves our compiler delivers real value.

What You'll Do

• Design and build a comprehensive performance testing platform for evaluating LLM inference workloads across GPU clusters
• Define and implement the benchmarking methodology, metrics, and test suites that measure latency, throughput, memory utilization, power consumption, and model accuracy
• Establish baseline performance for unoptimized models (Llama 3.2 70B, DeepSeek, etc.) and validate post-optimization improvements
• Develop automated testing pipelines for continuous performance validation across compiler releases and model updates
• Investigate performance bottlenecks using profiling tools (ROCm profilers, GPU traces, system-level monitoring) and work with the compiler team to drive optimizations
• Create dashboards and reporting that provide clear visibility into performance trends, regressions, and wins
• Collaborate cross-functionally with compiler engineers, ML engineers, and DevOps to ensure performance testing is integrated into our development workflow
• Document best practices for performance testing and optimization of ML workloads on GPU hardware

What You'll Bring

• 7+ years of experience in performance engineering, benchmarking, or systems engineering roles
• Deep understanding of ML inference workloads, particularly transformer-based models and LLMs
• Hands‑on experience with GPU programming and optimization (CUDA, ROCm, or similar)
• Strong programming skills in Python and C/C++
• Proven track record of building performance testing infrastructure or benchmarking platforms from scratch
• Experience with ML frameworks (PyTorch, TensorFlow, ONNX Runtime, vLLM, TensorRT‑LLM, etc.)
• Proficiency with profiling and debugging tools for GPU workloads
• Strong analytical skills with the ability to design experiments, analyze results, and communicate findings clearly
• Experience with CI/CD systems and test automation frameworks

Nice to Have

• Experience with AMD GPUs (Mi200/Mi300 series) and ROCm ecosystem
• Knowledge of compiler optimization techniques and their impact on performance
• Experience with distributed inference and multi‑GPU workloads
• Familiarity with ML model quantization, pruning, and other optimization techniques
• Background in high-performance computing or systems-level optimization
• Experience with infrastructure-as-code (Kubernetes, Docker, Terraform)
• Contributions to open-source ML or systems projects

Personal Attributes

• Obsessive about details — you notice the 2% regression that others miss
• Self-driven — you take ownership and don’t wait for permission to solve problems
• Collaborative mindset — you work well across teams and help others succeed
• Passionate about sustainability — you care about making AI more efficient and environmentally responsible
• Clear communicator — you can explain complex technical concepts to both engineers and stakeholders

Salary depends on experience and geographical location.

This salary range may be inclusive of several career levels and will be narrowed during the interview process based on a number of factors, such as the candidate’s experience, knowledge, skills, and abilities, as well as internal equity among our team.

Additional benefits for this role may include: equity, company bonus opportunities, medical, dental, and vision benefits; retirement savings plan; and supplemental wellness benefits.

Lemurian Labs ensures equal employment opportunity without discrimination or harassment based on race, color, religion, sex (including pregnancy, childbirth, or related medical conditions), sexual orientation, gender identity or expression, age, disability, national origin, marital or domestic/civil partnership status, genetic information, citizenship status, veteran status, or any other characteristic protected by law.

EOE