On 02/15/2017 02:03 PM, Yann Ylavic wrote:
On Wed, Feb 15, 2017 at 9:50 PM, Jacob Champion <champio...@gmail.com> wrote:
For the next step, I want to find out why TLS connections see such a big
performance hit when I switch off mmap(), but unencrypted connections
don't... it's such a huge difference that I feel like I must be missing
something obvious.
First, you did "EnableSendfile off", right?
Yep :) But thanks for the reminder anyway; I would have kicked myself...
Also, I have to retract an earlier claim I made: I am now seeing a
difference between the performance of mmap'd and non-mmap'd responses
for regular HTTP connections. I don't know if I actually changed
something, or if the original lack of difference was tester error on my
part.
Assuming so :) there is also the fact that mod_ssl will encrypt/pass
8K buckets at a time, while the core output filter tries to send the
whole mmap()ed file, keeping what remains after EAGAIN for the next
call (if any).
Oh, right... we split on APR_MMAP_LIMIT in the mmap() case. Which is a
nice big 4MiB instead of 8KiB. Could it really be as easy as tuning the
default file bucket size up?
--Jacob
