alt Hacker NewsYou can turn that off by setting or binding sb-ext:*evaluator-mode* to :interpret.
Also, on my machine, compiling the identity lambda form takes about 200 usec with (optimize (compilation-speed 3) (debug 0)). SBCL could use a faster JIT mode, perhaps at compilation-speed 3/speed 0. Perhaps there are some other internal special variables that could be tweaked to reduce compile time.
Are you sure this is actually makes a difference in your build?
Mine doesn't have the SB-INTERPRETER package, so I doubt binding the variable has an effect.