Response Time Tests
The last common test is one that measures response time: the amount of time that elapses
between the sending of a request from a client and the receipt of the response.
The difference between a response time test and a throughput test (assuming the latter is
client-server based) is that client threads in a response time test sleep for some period of time
between operations. This is referred to as think time . A response time test is designed to
mimic more closely what a user does: she enters a URL in a browser, spends some time read-
ing the page that comes back, clicks on a link in the page, spends some time reading that
page, and so on.
When think time is introduced into a test, throughput becomes fixed: a given number of cli-
ents executing requests with a given think time will always yield the same TPS (with some
slight variance; see sidebar). At that point, the important measurement is the response time
for the request: the effectiveness of the server is based on how quickly it responds to that