Help: Why is only one copy running even if I specified multiple copies? about nbomber HOT 11 CLOSED

var scenario = Scenario.Create("MultiThread", async scenectx =>
        {
            var callIndex = scenectx.InvocationNumber;

            scenectx.Logger.Warning($"INSTANCE NUMBER {callIndex}");

            return Response.Ok();
        })
        .WithoutWarmUp()
        .WithLoadSimulations(
            Simulation.IterationsForConstant(copies: 4, iterations: 4)
        );

from nbomber.

var scenario = Scenario.Create("MultiThread", async scenectx =>
        {
            var callIndex = scenectx.InvocationNumber;

            scenectx.Logger.Warning($"INSTANCE NUMBER {callIndex}");

            return Response.Ok();
        })
        .WithoutWarmUp()
        .WithLoadSimulations(
            Simulation.IterationsForConstant(copies: 4, iterations: 4)
        );

Thanks for your response. I ran your code and got the following log:

2024-04-12 23:06:37.263 +08:00 [WRN] [ThreadId:7] INSTANCE NUMBER 1
2024-04-12 23:06:37.265 +08:00 [WRN] [ThreadId:7] INSTANCE NUMBER 2
2024-04-12 23:06:37.265 +08:00 [WRN] [ThreadId:7] INSTANCE NUMBER 3
2024-04-12 23:06:37.265 +08:00 [WRN] [ThreadId:7] INSTANCE NUMBER 4

The ThreadId is same (7), but what I want is 4 different ThreadId. How can I get copies running on different threads?

from nbomber.

It's because of the scheduling. NBomber is using TPL (Task library) for multithreading. Please try to introduce some await like task.Delay() inside your scenario. And also run more iterations.

from nbomber.

Since your load test does nothing the scheduler is quite smart to optimise it. Try to introduce some pause or send HTTP request for example.

from nbomber.

Since your load test does nothing the scheduler is quite smart to optimise it. Try to introduce some pause or send HTTP request for example.

Thanks! I used the following code to print the invocation count of each instance:

using NBomber.CSharp;

int NCOPY = 4;
int[] counts = new int[NCOPY];
counts.AsSpan().Fill(0);

var scenario = Scenario.Create("MultiThread", async scenectx =>
{
    int threadIndex = scenectx.ScenarioInfo.InstanceNumber;
    lock (counts)
    {
        counts[threadIndex]++;
    }

    await Task.Delay(5);
    
    return Response.Ok();
})
.WithoutWarmUp()
.WithLoadSimulations(
    Simulation.IterationsForConstant(copies: 4, iterations: 100)
);

NBomberRunner.RegisterScenarios(scenario).Run();

for (int i = 0; i < counts.Length; i++)
    Console.WriteLine($"Instance {i} called {counts[i]} times.");

When I use await Task.Delay(5); I got:

Instance 0 called 3 times.
Instance 1 called 51 times.
Instance 2 called 0 times.
Instance 3 called 46 times.

When I use await Task.Delay(500); I got:

Instance 0 called 25 times.
Instance 1 called 26 times.
Instance 2 called 24 times.
Instance 3 called 25 times.

I want to mock the situation that 4 threads are calling my method at the same time, so I need to get invocations distributed on each scenario instance equally. But it seems impossible when my method is fast. How can I reach my purpose?

from nbomber.

For benchmarking, I suggest you to look at https://benchmarkdotnet.org/

from nbomber.

For benchmarking, I suggest you to look at https://benchmarkdotnet.org/

Actually I need to do load test with a set of different test cases, and measure the average time and other statistics on the set. But BenchmarkDotNet will do benchmarking on each case separately, which cannot satisfy my need.

from nbomber.

btw you dont need lock here, NBomber will run each scenario on dedicated Task/Thread

lock (counts)
{
    counts[threadIndex]++;
}

from nbomber.

Try to use Iterations for Inject.

from nbomber.

Ah sorry, I am wrong about your usage of lock. You need to use it.
If you work with primitive number I suggest you consider Interlocked.Increment

from nbomber.

@AntyaDev Thank you for your advice. I am trying KeepConstant simulation now. This seems to be a good choice.

from nbomber.