It's plotting the relative speedup of each router's benchmark vs the slowest benchmark on that dataset. (For example, Beego's performance on the GithubStatic dataset was 12 times faster than the slowest GithubStatic dataset performance)
Fastest overall routers are sorted left to right. Keep in mind that the vertical scale is logarithmic, so implementations on the left are more than 100 times faster than those on the far right.
One thing that affects Gorilla mux is that this test is putting all the routes at the top-level instead of constructing subroutes based on the logical route hierarchies.
Certainly the fact that HttpRouter constructs that prefix tree for you is a huge feature, and the speed is impressive, but it's not a typical/canonical usage of Gorilla mux.
I don't know if that's the case with the other routers or not.
