The document summarizes a performance analysis study of a large enterprise application called Zanzibar. The researchers initially struggled to get the application to scale even on modest hardware. Through analyzing javacores, they identified and addressed multiple bottlenecks, including lock contention, disk throughput issues, and inefficient Java code. These changes resulted in performance improvements of 1.4-5x. The researchers also developed the WAIT performance tool to help identify primary bottlenecks in deployed applications with low overhead. The tool uses standard OS and JVM data and has seen widespread adoption due to its ease of use.