Need different test duration for different concurrencies

[thameem-abbas]

As it stands, we have a constant test duration for all concurrencies. This wastes valuable test time.
For a concurrency config such as this:

[1,2,4,8,16,32,64,128,256,512]
At concurrency of 512, It would take 3 minutes or more to have a decent steady state phase in the test. On the other hand, at concurrency of 1, there is no real need to run for 3 minutes.
As it stands, this set of tests would take at least 30 minutes (if set to 3 minutes) but in practice at least 40 minutes for the trailing requests to finish.

If we can tune the test duration along with the concurrency, this would allow us to bring it down considerably.
For example,

• 1, 2, 4, and, 8 can be run at 1 minute test duration
• 16 and 32 can be run at 2 minutes test duration
• 64 and 128 at 3 minute test duration
• 256 and 512 at higher test duration.

This can be brought down to around 22 minutes with the trailing requests bringing the total to about 26 or 27 minutes.

A saving of about 30% time.

[thameem-abbas]

Following on what I have mentioned above, we also probably need a way to test purely the steady state performance. That would be the best performance someone can achieve in a well tuned real world workload. We have segments of test duration where we might be testing at potentially sub-optimal load. Will try and produce data to back this up.