“The mean wall-time reduction was a healthy 5.59%. Around half of this was due to some huge recent improvements in rustdoc, which saw a mean wall-time reduction of 37.92%!”
Since December the compiler is 5.59 percent faster on mean wall time, and rustdoc on its own is down 37.92 percent. One benchmark went from 27 seconds to under a second on the new trait solver. Nethercote profiled a workload, found almost half its time sitting in memcpy, and shrank AST expression nodes from 72 bytes to 64. No rewrite and no announcement. This is what performance work looks like when somebody actually does it.