---
title: "Per VU iterations | Grafana k6 documentation"
description: "Each VU executes an exact number of iterations."
---

# Per VU iterations

With the `per-vu-iterations` executor, each VU executes an exact number of iterations. The total number of completed iterations equals `vus * iterations`.

## Options

Besides the [common configuration options](/docs/k6/latest/using-k6/scenarios/#options), this executor has the following options:

Expand table

| Option      | Type    | Description                                                                        | Default |
|-------------|---------|------------------------------------------------------------------------------------|---------|
| vus         | integer | Number of VUs to run concurrently.                                                 | `1`     |
| iterations  | integer | Number of `exec` function iterations to be executed by each VU.                    | `1`     |
| maxDuration | string  | Maximum scenario duration before it’s forcibly stopped (excluding `gracefulStop`). | `"10m"` |

## When to use

Use this executor if you need a specific number of VUs to complete the same number of iterations. This can be useful when you have fixed sets of test data that you want to partition between VUs.

## Example

The following example schedules 10 VUs to execute 20 iterations *each*. The test runs 200 total iterations and has a maximum duration of 30 seconds.

JavaScript ![Copy code to clipboard](/media/images/icons/icon-copy-small-2.svg) Copy

```javascript
import http from 'k6/http';
import { sleep } from 'k6';

export const options = {
  discardResponseBodies: true,
  scenarios: {
    contacts: {
      executor: 'per-vu-iterations',
      vus: 10,
      iterations: 20,
      maxDuration: '30s',
    },
  },
};

export default function () {
  http.get('https://test.k6.io/contacts.php');
  // Injecting sleep
  // Sleep time is 500ms. Total iteration time is sleep + time to finish request.
  sleep(0.5);
}
```

## Observations

The following graph depicts the performance of the [example](#example) script:

Based upon our test scenario inputs and results:

- The number of VUs is fixed at 10, and are initialized before the test begins;
- Total iterations are fixed at 20 iterations per VU, i.e. 200 iterations, `10 VUs * 20 iters each`;
- Each *iteration* of the `default` function is expected to be roughly 515ms, or ~2/s;
- Maximum throughput (highest efficiency) is therefore expected to be ~20 iters/s, `2 iters/s * 10 VUs`;
- The maximum throughput is reached, but not maintained;
- Because the distribution of iterations is even among VUs, a *fast* VU may finish early and be idle for the remainder of the test, thereby lowering *efficiency*;
- Total duration of 9 seconds is slightly longer than [shared iterations](/docs/k6/latest/using-k6/scenarios/executors/shared-iterations/) due to lower efficiency;
- Overall test duration lasts as long as the *slowest* VU takes to complete 20 requests.