On Thu, 16 Feb 2017, Yann Ylavic wrote:
Here are some SSL/core_write outputs (sizes) for me, with 2.4.x.
This is with a GET for a 2MB file, on localhost...
Please note that "EnableMMap on" avoids EnableSendfile (i.e.
"EnableMMap on" => "EnableSendfile off"), which is relevant only in
the http (non-ssl) case anyway.
Outputs (and the patch to produce them) attached.
TL;DR:
- http + EnableMMap => single write
- http + !EnableMMap + EnableSendfile => single write
- http + !EnableMMap + !EnableSendfile => 125KB writes
- https + EnableMMap => 16KB writes
- https + !EnableMMap => 8KB writes
If you try larger filesizes you should start seeing things being
broken into chunks even for mmap/sendfile. For example we have
#define AP_MAX_SENDFILE 16777216 /* 2^24 */
which is unneccessarily low IMHO.
Think being able to do 100 Gbps single-stream effectively, that's what
we need to optimize for now in order to have it in distros some years
from now. And you will waste a lot of CPU doing small writes at those
speeds...
While I applaud the efforts to get https to behave performance-wise I
would hate for http to be left out of being able to do top-notch on
latest&greatest networking :-)
Granted, latest&greatest CPU:s "only" seem to be able to do approx 5
GB/s AES128 per core so it will be hard to reach 100 Gbps
single-stream https, but I really think we should set the goal high
while at it...
/Nikke
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Niklas Edmundsson, Admin @ {acc,hpc2n}.umu.se | ni...@acc.umu.se
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Memory allocation error: Reboot System!
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