It was not written to cope with the number of file modification requests it now receives.

Then you need to identify where the limitation lies.

• Is it that the web-server can only service a limited number of concurrent connections?
• Or that the server hardware cannot cope with processing the number of concurrent requests?

  If this is the case, then there are three possible reasons:

  1. The web server has a (programmed) limit on the number of concurrent connections it will allow.

     Use a better web server.

  2. The server hardware max's out all its cpus/cores and can still not keep up with demand.

     Purchase bigger hardware. Or a employ/purchase a second (or more) box(s) and have the web server hand off (distribute) the cpu intensive processing across the boxes. </ii>

  3. The web-server is unable to utilise all the cpus/cores the hardware has available.

     Use a better web server.

     Or, run multiple copies of the existing one on different ports and have the front-end (running on the current port) redirect the incoming connects to the other ports for service.

You are probably better off using an existing web server, than trying to write your own in Perl. It doesn't have to be a behemoth like Apache, something simple and efficient like Thttpd is probably a better choice for something like this.