Elisp Bytecode Compilation for Speed

My Emacs startup time was stretching beyond 10 seconds, which seemed a bit offputting even for a text editor cum operating system. I do have a fair amount of elisp loading at startup, however, and though I have played with byte-code-cache, I determined there must be an easier way to compile all my elisp files in one go, rather than calling byte-compile-file for each file in my elisp directory.  It turns out there is:

C-0 M-x byte-recompile-directory

will recursively traverse a directory stucture and compile all .el files encountered.  My startup time is back to 4 seconds.