How to measure the start to endtime of a thread in JMeter - jmeter

Question

I have been trying to figure out how to measure the amount of time it takes a thread (virtual user) in JMeter to fully complete. I'm not necessarily concerned with response times at the moment. The API that I'm attempting to load test works in an async fashion. I make a request to start a job, I'm given a job id then I use that job id to check the status of said job until it's complete. I'm interested in knowing how long it takes for each job to complete i.e. when the job starts (thread is created) and when the job is completed (thread is done working).
I've seen several people suggest using the Transaction Controller in similar situations but that, unless I'm misunderstanding, gives me the total response time for all the requests in the "transaction" which doesn't help me.
This is what I have setup so far in JMeter:
Which actually works great, I make the initial request to submit the job and extract the job id. In a while loop I check the status of the job using the extracted id every 10 seconds (Constant Timer) until the job is complete.
This is what the aggregate report looks like for 5 concurrent users, I can also make the labels be the same so that it's compacted further but none of this information tells me how long a thread took. From the number of samples I can surmise that half the threads took roughly 10 seconds to complete and the others I can multiply by 10 seconds (sleep timer) and get a rough estimate how long it took to complete but that would be difficult to do (or at least time intensive) for a couple hundred threads. I was really hoping JMeter had something out of the box that would give me this information in a nice report format.
I've also seen suggestions that the only way to get this type of information is to parse logs, was just wondering if anyone has solved a similar problem.

Answer 1

Your question contains the answer, just measure it
Add JSR223 Sampler to the beginning of your Thread Group and put the following code into "Script" area:
SampleResult.setIgnore()
vars.putObject('startTime', System.currentTimeMillis())
the first line tells JMeter to not to store the JSR223 sampler result (as I believe you don't need this) and the second line saves current timestamp into ${startTime} JMeter Variable
Add another JSR223 Sampler to the end of your Thread Group and use the following code there:
SampleResult.setIgnore()
def end = System.currentTimeMillis()
def start = vars.getObject('startTime')
log.info('Thread ' + (ctx.getThreadNum() + 1) + ' elapsed time: ' + (end - start))
here we get the current timestamp after the job ended and subtract it from the previous timestamp store in the first JSR223 Sampler. The delta is printed to jmeter.log file however you might rather want to store it into another JMeter Variable and expose it to the results via Sample Variables property so it would be added to .jtl results file
Demo:
See Top 8 JMeter Java Classes You Should Be Using with Groovy to learn more about what these SampleResult, vars, and ctx shorthands mean