Hey...
I've been doing some benchmarks on mod_file_cache, and I'm getting
numbers that confuse the hell out of me. Here's what I've seen (this is
on a RHL 7.1 box with kernel 2.4.3 running on an AMD Athlon 1.2GHz with
1GB RAM, using /manual/index.html.en as the test file):
Request for static file:
No keepalives Keepalives
-------------------------- ----------------------------
no cache 118.98 req/s 676.92 KB/s 2280.06 req/s 13053.79 KB/s
CacheFile 90.19 req/s 511.21 KB/s 2181.21 req/s 12440.95 KB/s (WTF?!)
MMapFile 80.90 req/s 458.54 KB/s 1978.32 req/s 11283.72 KB/s (WTF?!)
Request for server-parsed file:
No keepalives Keepalives
-------------------------- ----------------------------
no cache 31.81 req/s 183.68 KB/s 453.38 req/s 2647.38 KB/s
CacheFile 87.20 req/s 501.66 KB/s 682.49 req/s 3965.77 KB/s
MMapFile 104.17 req/s 599.30 KB/s 674.94 req/s 3925.77 KB/s
Clearly there's something screwy going on (as seen in the static file
case). I verified with gdb that sendfile IS being used in the static
tests with both the cached and non-cached file handles (I also examined
those apr_file_t's and they looked right). Maybe a 5KB file should be
below the sendfile() threshold on Linux? That doesn't explain why it goes
SLOWER using sendfile on a cached file handle than it does using sendfile
on a file handle it has to open up on every request. Maybe it's
something with the apr_sendfile() implementation on Linux? I've looked
at it and no problems jump right out at me, though. I'm stumped.
Anyway, I don't consider this a showstopper for the T&R, because it serves
the requests correctly (one way or another) without segfaulting... but
clearly I need to figure out what's going on at some point soon.
(On the other hand, these results tell me that you get a nifty keen
speedup by using mod_file_cache to accelerate server-parsed requests under
2.0 (as I'd hoped), which is something you couldn't really do in 1.3. :-)
--Cliff
--------------------------------------------------------------
Cliff Woolley
[EMAIL PROTECTED]
Charlottesville, VA
