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This product reached the end of support date on March 31, 2021.

Page [Response] Time Breakdown in CAS adds up to > 100%

matt_lewis
Dynatrace Advisor
Dynatrace Advisor

Hey guys,

Just a question that has come up around Synthetic data in the CAS.  In the Synthetic Backbone Pages report, there is a metric called Page Time Breakdown.  I would assume that the sum of all the components (DNS Time, Connect Time, SSL Time, 1st Byte Time, and Content time) would all add up to 100%.  I have run in to several instances of the Page Time Breakdown adding up to more than 100% (see screenshot).

Can anyone explain why this is?  I have seen all of the different metrics (DNS Time, Connect Time, SSL Time, 1st Byte Time, and Content time) at one time or another equal more than 100% by itself.

Any explanation would be appreciated.

Thanks,

Matt

2 REPLIES 2

ulf_thorn222
Inactive

Hi

This has twisted many heads so you're in good company.

Basically there is two ways of accounting for time in there:

  1. The actual wall-clock time. This is what most people can immediatly relate to.
  2. The SUM of all requests, some happening in paralell. This is where most people slip since it's not always obvious and the result is always more than the wall-clock time.

What you want to pursue with this last metric is f.ex. that if you have a gazillion objects, your "Connect Time" will take an proportionate lionshare since it will take time setting up the request for the object. If you have a large number of hosts, the DNS time (can be the bulk of the time. So the key is to monitor how the metrics there behave in relation to each other.

 

Excellent, I figured that there was something I was not accounting for.  Thanks for following up with the explanation!