Hubble: Performance Debugging with In-Production, Just-In-Time Method Tracing on Android

Hubble is a method-tracing system shipped on all supported and upcoming Android devices manufactured by Huawei, in order to aid in debugging performance problems. Hubble instruments every non-inlined bytecode method's entry and exit to record the method's name and a timestamp. Instead of persisting all data, trace points are recorded into an in-memory ring buffer where older data is constantly overwritten. This data is only persisted when a performance problem is detected, giving engineers access to invaluable, detailed runtime data Just-In-Time before the detected anomaly. Hubble is highly efficient, with its tracing inducing negligible overhead in real-world usage and each trace point taking less than one nanosecond in our microbenchmark. Hubble significantly eases the debugging of user-experienced performance problems and has enabled engineers to quickly resolve many bug tickets that were open for months before Hubble was available.