Superpack: Pushing the limits of compression

Superpack: Pushing the limits of compression

摘要

Managing app size at Facebook is a unique challenge: Every day, developers check in large volumes of code, and each line of code translates into additional bits in the apps that people ultimately download onto their phones. Left unchecked, this added code would make the app bigger and bigger until eventually the time it takes to download would become unacceptable. Compression is one of the methods we use to keep app size minimal. These compressed files take up less space, which means smaller apps that download faster and use less bandwidth for billions of users around the world. Such savings are especially important in regions where mobile bandwidth is limited, making it costly to download large apps. But compression alone isn’t enough to keep pace with all the updates we make and features we add to our apps. So we developed a technique called Superpack, which combines compiler analysis with data compression to uncover size optimizations beyond the capability of traditional compression tools. Superpack pushes the limits of compression to achieve significantly better compression ratios than existing compression tools.