基于公式计算JMeter步进线程组执行时长的技术问题

I've translated your Java code logic into a set of mathematical formulas so you can compute the total execution duration of a Stepping Thread Group directly, without relying on code loops. Let's break this down step by step:

First, let's define all the input parameters (matching your code variables):

• TotalThreads: Total number of threads to run
• firstWait: Initial wait time before starting any threads (seconds)
• thenStart_threads: Number of threads launched in the first batch
• nextAdd_threads: Number of threads added in each subsequent batch
• threadsEverySeconds: Interval between starting subsequent thread batches (seconds)
• usingRamupSeconds: Ramp-up time to launch a batch of threads (seconds)
• holdForSeconds: Duration to run all threads at full capacity (seconds)
• finallyStopThreads: Number of threads stopped in each batch during ramp-down
• down_threadsEverySeconds: Interval between stopping subsequent thread batches (seconds)

1. Ramp-Up Phase Duration #

This covers the time from initial wait to launching all threads. We split this into two scenarios based on whether you have an initial thread batch:

Scenario 1: thenStart_threads > 0 #

1. Initial batch setup: Time to wait, launch the first batch, and wait for the next interval:

   initial_ramp = firstWait + usingRamupSeconds + threadsEverySeconds
   

2. Remaining threads to launch:

   RemainingThreads = TotalThreads - thenStart_threads
   

3. Calculate full batches and final partial batch:
   • Number of complete batches of nextAdd_threads threads:

     full_batches = floor( (RemainingThreads - 1) / nextAdd_threads )
     

     (We subtract 1 to ensure the final full batch doesn't include an extra interval)
   • Threads in the final (possibly partial) batch:

     final_batch_threads = RemainingThreads - (full_batches * nextAdd_threads)
     

4. Time for remaining batches:
   • Time for all full batches (each includes ramp-up + interval):

     full_batches_time = full_batches * (usingRamupSeconds + threadsEverySeconds)
     

   • Time for the final batch:

     final_batch_time = if final_batch_threads == nextAdd_threads 
                        then usingRamupSeconds 
                        else (final_batch_threads / nextAdd_threads) * usingRamupSeconds
     

5. Total ramp-up time:

   rampupTime = initial_ramp + full_batches_time + final_batch_time
   

Scenario 2: thenStart_threads = 0 #

Skip the initial batch setup, start with the initial wait time, then calculate remaining batches the same way:

rampupTime = firstWait + full_batches_time + final_batch_time

(Use the same RemainingThreads = TotalThreads, full_batches, and final_batch_time calculations as above)

2. Ramp-Down Phase Duration #

This covers the time to stop all threads after the hold phase. The logic is: we stop finallyStopThreads threads each interval, and don't need an interval after the final stop:

RampDown = ( (TotalThreads // finallyStopThreads) - 1 ) * down_threadsEverySeconds

(The // denotes integer division, matching your Java code's behavior)

3. Total Execution Duration #

Add up all three phases to get the total runtime:

TotalDuration = rampupTime + holdForSeconds + RampDown

Example Validation (Using Your Code's Parameters) #

Let's test with your sample values:

TotalThreads=500, firstWait=25, thenStart_threads=5, nextAdd_threads=25, threadsEverySeconds=30, usingRamupSeconds=5, holdForSeconds=600, finallyStopThreads=25, down_threadsEverySeconds=25

1. RemainingThreads = 500 - 5 = 495
2. full_batches = floor( (495-1)/25 ) = 19
3. final_batch_threads = 495 - (19*25) = 20
4. final_batch_time = (20/25)*5 = 4
5. initial_ramp = 25 +5 +30 = 60
6. full_batches_time =19*(5+30)= 665
7. rampupTime=60+665+4=729
8. RampDown=(500//25 -1)*25= (20-1)*25=475
9. TotalDuration=729+600+475=1804

This matches the output from your Java code perfectly, confirming the formulas work.

内容的提问来源于stack exchange，提问作者Raju