mod_include performance update

[Brian Pane <bp...@pacbell.net>]

The good news:

With some of the recent performance patches (thanks to Justin for all
the commits), the throughput of 2.0 on SSI requests has improved quite
a bit.  IanH ran the old and new code through his benchmark setup in
which clients request a .shtml file with two included files (threaded mpm,
Solaris, 8-CPU server).  The latest CVS code has about 60% higher throughput
than the code base from a week ago.

  http://webperf.org/a2/v25/

The bad news:

The usr CPU usage (see the 'server stats' links on the benchmark results
pages) is roughly equal to the sys CPU usage.  Even for SSI requests, I'm
surprised that the percentage of usr CPU is that high.  (To look at it from
a more positive angle, these numbers mean that there may be 
opportunities for
significant additional speedups.  Time to do some more profiling...)

One phenomenon in the truss data looks a bit strange:
  http://webperf.org/a2/v25/truss.2001_01_04

The server appears to be logging the request (the write to file descriptor
4) before closing its connection to the client (the shutdown that 
follows the
write).  For a non-keepalive request, shouldn't it do the shutdown first?

--Brian