+=head1 DESCRIPTION
+
+This is usually the preferred backend, providing persistent processes
+for speeds comparable to L<mod_perl|PLP::Backend::Apache> and
+reliability closer to L<CGI|PLP::Backend::CGI>.
+
+Servers often feature auto-adjusting number of daemons, script timeouts,
+and occasional restarts.
+
+=head2 Configuration directives
+
+PLP behaviour can be configured by setting environment variables.
+
+=over 16
+
+=item PLP_CACHE
+
+Sets caching off if false (0 or empty), on otherwise (true or undefined).
+When caching, PLP saves your script in memory and doesn't re-read
+and re-parse it if it hasn't changed. PLP will use more memory,
+but will also run 50% faster.
+
+=back
+