Difference in response time between http vs https

Question

I tested my web site with 100 users with http and https. The response time obtained in https is much higher compared to the response time obtained in http. The response time of https is nearly four times greater than http. Can anyone explain me why the response time is higher in https compared to http? or do i need to change any SSL property in jmeter system.properties? Thanks in Advance..!

Answer 1

SSL Handshake assumes 4 requests for establishing a connection so first request should be something like 4x times longer than in case of HTTP. See The SSL handshake diagram for more info

However if you receive 4 times performance degradation for all requests - that doesn't sound right.

There are following JMeter properties which control SSL flows:

• https.sessioncontext.shared - controls whether SSL session contexts are created per thread (if it's set to false) or shared (if it's set to true)
• https.use.cached.ssl.context - controls if cached SSL context is being reused between iterations

These properties live in jmeter.properties file under /bin folder of your JMeter installation. It's also possible to override them using -J command line key as follows:

jmeter -Jhttps.sessioncontext.shared=true -Jhttps.use.cached.ssl.context=true 

See Apache JMeter Properties Customization Guide for more details.

If above setting won't help you'll need to review your test plan and perhaps profile application to see where this extra time is spent.