(Copying from Q&A) Before starting out some time ago, I did some experiments with bup. I had a good experience with bup and high expectations for it. However, I found that quite a lot of performance was left on the table, so I was motivated to start elfshaker. Unfortunately that time has past so I don't have scientific numbers for you measured with other software at this time.

As an idea of how elfshaker performs, we see ~300ms time to create a snapshot for clang, and ~seconds-to-minute to create a binary pack containing thousands of revisions. Extraction takes less than a second. One difference of elfshaker compared with some other software I tested is that we do the compression and decompression in parallel, which can make a very big difference on today's many-core machines.