First byte time grade / https

Web Performance Discuss Test Results
1

Does the first byte time grading take into account whether the site is http or https ?

2

Yes. The SSL negotiation time is added to the baseline time (basically ignored).

3

Could it make sense to have a higher target first byte time for https sites, since they will always be slower than http ?

4

It does have a higher target - the SSL negotiation time is added to the target time that it would have received otherwise.

5

I’ve a https page which is rated D with :

First Byte Time (back-end processing): 65/100
447 ms First Byte Time
105 ms Target First Byte Time

From the chart :
Start Offset: 0.001 s
DNS Lookup: 5 ms
Initial Connection: 36 ms
SSL Negotiation: 361 ms
Time to First Byte: 43 ms

Which looks like it meets the target first byte time of 105ms, when SSL is excluded.

6

Any chance you can share the test result (feel free to mail it to me at pmeenan@webpagetest.org if you don’t want to post it here). Sounds like a bug that should be pretty easy to track down (and since the grade is calculated on the fly on the server I can fix it retroactively)

Thanks,

-Pat

7

Email sent.

8

All fixed, thanks. It’s one of those embarrassingly stupid mistakes where a single missing character causes subtle mistakes (in this case I forgot to put a $ in front of the sslTime variable).

9

Thanks for fixing it so quickly - I’m now getting an A rating.

Just a thought - it might be worth having a fixed SSL target time too, so that a site with slow ssl negotiation gets a lower rating.

10

Hi Patrick,

I am running the private instance in my machine and I face the similar problem discussed in this thread. The target first byte time is the time needed for DNS, socket and SSL negotiations + 100ms, but the value that I see in my results are not matching this formula. Thus, I always see ‘F’ grade for first byte time.

I ran the performance test for the url https://gmail.com through webpagetest.com and the results can be found at http://www.webpagetest.org/result/120207_KS_34SGK/. For some reason, I am not seeing the ssl negotiations time in this result. I noticed the target first byte time is not matching the total of breakdown values.

And, I also ran the performance test for the url https://gmail.com through private instance and noticed the target first byte time value is not according to the above formula.
Results from the private instance:

First Byte Time (back-end processing): 45/100
846 ms First Byte Time
300 ms Target First Byte Time

URL: https://accounts.google.com/ServiceLogin?service=mail&passive=true&rm=false&continue=https://mail.google.com/mail/&ss=1&scc=1&ltmpl=default&ltmplcache=2
Host: accounts.google.com
IP: 74.125.53.84
Error/Status Code: 200
Start Offset: 0.527 s
DNS Lookup: 30 ms
Initial Connection: 70 ms
SSL Negotiation: 141 ms
Time to First Byte: 78 ms
Content Download: 1057 ms
Bytes In (downloaded): 15.4 KB
Bytes Out (uploaded): 1.5 KB

Also, please correct me if my understanding is wrong.

Thanks

11

Redirects count against the first byte time which is probably where the discrepancy is.