DoneCal (my simple calendar and time sheet substitute web app) now has HTTPS support. It's not enabled yet as I'm ironing out some more testing. Basically, HTTPS is, at least at the moment, only going be available to premium users. Anyway, this is a performance story and about the difference in speed between HTTP and HTTPS.

I'll let these unscientific benchmarks speak for themselves.

HTTP:

donecal:~# ab -n 1000 -c 10 "http://donecal.com/api/events.json?guid=xxx&start=1292999600&end=1293294812"
...
Document Length:        616 bytes
Failed requests:        0
...
Requests per second:    1432.40 [#/sec] (mean)
...
Transfer rate:          1184.81 [Kbytes/sec] received

HTTPS:

..
Server Port:            443
SSL/TLS Protocol:       TLSv1/SSLv3,DHE-RSA-AES256-SHA,2048,256

...
Document Length:        616 bytes
Failed requests:        0
...
Requests per second:    84.73 [#/sec] (mean)
...
Transfer rate:          70.08 [Kbytes/sec] received

That's quite a huge difference in requests per second. HTTPS 17 times slower than HTTP. Is this the reality of HTTPS? Or something wrong with my cert or something wrong with running HTTPS through ab?

Anyway, this pretty good me thinks anyway. The HTTP version is over 1,400 requests per second and this is a fully database, security and encoding involving application. This particular test data (616 bytes JSON) isn't big but it sure is bigger than some of the "'hello world'" benchmarks you see on the interweb.

UPDATE

See this new entry about enabling ssl_session_cache in Nginx

Chris Adams - 27 December 2010 [«« Reply to this]
HTTPS is considerably slower for time to first request because you have SSL session negotiation: if you test ab with and without -k you should see an enormous boost when reusing the same connection.

In practice this is fine as long as you have your SSL session cache configured (http://wiki.nginx.org/HttpSslModule#ssl_session_cache) since client browsers won't negotiate a new session every time. At that point you're left hoping everyone adopts some of the performance tweaks for avoiding extra round-trips (e.g. http://www.imperialviolet.org/2010/06/25/overclocking-ssl.html) but it's usually manageable for non-realtime apps.
Peter Bengtsson - 30 December 2010 [«« Reply to this]
Thanks for the tip Chris! I'm reading up on it now.
Peter Bengtsson - 31 December 2010 [«« Reply to this]
Hi Chris,
Check out my update regarding ssl_session_cache
http://www.peterbe.com/plog/ssl_session_cache-ab
Chris Adams - 31 December 2010 [«« Reply to this]
Nice! Seeing that jump does make me wonder if the defaults should be changed, though, as it's pretty impressive for a one-liner.


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