Memoro is a heap profiler built using the LLVM Sanitizer infrastructure. It instruments your program during the compilation and its visualiser helps you navigate the collected profile by highlighting bad patterns, such as frequent allocation and waste of memory. Collecting data proved to be a challenge: instrumented programs don’t meet our expectations and the run-time overhead makes Memoro impractical to use on larger services. This talk presents our work to overcome those constraints, understand the source of the overhead and reduce it, so Memoro can be applied more easily on Facebook services.