I had to come up with some way to cache dynamic files that I have to serve, so I ended up with a bunch of static files which I served by a simple function:
(defun file-to-string (path)
  "Reads a file into a string"
  (if (probe-file path)
      (with-open-file (in path)
        (let ((str (make-string (file-length in))))
          (read-sequence str in)
          str))))

The performance was very good, but then I thought that it's not the proper way to serve static files as there is a hunchentoot function handle-static-file.
When I started using the hunchentoot's function the response time almost tripled and when I run "top" program to monitor CPU usage it jumps up to 60% (on my PIII 600 MHz) CPU,
whereas using file-to-string CPU usage stays with 2% (maybe because the serving time is much shorter top doesn't catch that CPU peak).
My question is what could be the reason I see this behaviour? (I am using SBCL 1.0.15 with latest dependences of hunchentoot-0.15.7)

Thank you,
Andrew