Very high CPU consumption, Best approach for CPU usage

mediasoup libraries
1

Hi,
I am developing a video conferencing app. Right now my settings are 1 worker and 1 router.
So in a room, there were 4 producer and 12 consumer. but the CPU consumption goes upto 75%, I am using 8 core cpu. So what are the best ways we can adopt? Is there any kind of settings we can turn off?
Really thanks for your help

2

To use the full power of your server you need to create worker per CPU core and try to balance routers between workers so each worker has a fair number of participants (producers+consumers).

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3

This is an example of code you would use to solve the problem mkh is describing above.

Basically, you want to create a worker for each virtual CPU core and then attempt to evenly distribute new routers across the workers. (balancing the load)

Here’s a piece of example code I use:

const os = require('os')
const mediasoup = require('mediasoup')

// Get the count of total virtual CPU cores
const numWorkers = Object.keys(os.cpus()).length
let lastUsedWorkerIndex = -1

module.exports = {
  // Create all mediasoup workers (runs once at launch)
  createWorkers: async () => {
    console.log("****CREATING MEDIASOUP WORKERS****")
    for(let i = 0; i < numWorkers; i++) {
      const worker = await mediasoup.createWorker({
        logLevel: "debug"
      })
     // Add worker to workers array
      workers.push(worker)
    }
    console.log(`****CREATED ${numWorkers} MEDIASOUP WORKERS ****`)
  },

  // Get a worker from a CPU core, balances load across CPU
  getWorker: () => {
    lastUsedWorkerIndex++
    if (lastUsedWorkerIndex >= numWorkers) {
      lastUsedWorkerIndex = 0;
    }

    return workers[lastUsedWorkerIndex]
  }
}

The only thing to take into consideration here is that the function for deciding (getWorker()) what worker to create a new router on is very simplistic. It just goes through the workers linearly and doesn’t check the load of each worker. eg: If Worker 1 had 80% CPU core usage, and Worker 2 had 20% CPU core usage, obviously you would assign a new router to Core 2. But the function used above for getting a worker wont come to that conclusion. But this is a start.

3 Likes
4

Note that now you can even check per Worker resource usage to decide which Worker to assign to a new Router:

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5

Just in case: https://mediasoup.org/documentation/v3/scalability/

1 Like
6

Thanks you for this code, Really appreciate it.

7

Actually I have tried that, its not working. Its giving error like getResourceUsage is not a function.

worker = await mediasoup.createWorker(mediasoupOptions.worker);
const usage = await worker.getResourceUsage()

8
1 Like
9

If I’m correct, I think that function is new in v3.4.0. https://github.com/versatica/mediasoup/blob/v3/CHANGELOG.md. I’d check to see if you are on at least that version.

10

I am on 3.2.5. I will update now. Thanks

11

Interesting!
However it seems not that easy to turn the struct into a comparable value. :face_with_monocle:

12

man getrusage

https://linux.die.net/man/2/getrusage

I don’t even know how to properly use those values. But they are there.

13

FWIW, here’s how I calculate load. I don’t know if this is 100% correct, but it does appear to work.

The trick here, is that ru_stime and ru_utime are monotonically increasing, and are represented in milliseconds. Therefore, we just need to take slices of time, and compute the load over that slice of time.

async scheduleResourceUsage (timeout) {
    this.updateResourceUsage()
    this.timeout = setTimeout(() => this.scheduleResourceUsage(timeout), timeout)
  }

  async updateResourceUsage () {
    const { workerLoads, log } = this
    let updatedCPULoad = false
    for (const worker of this.workers) {
      const usage = await worker.getResourceUsage()
      const wall = Date.now()
      const { ru_stime: systemTime, ru_utime: userTime } = usage
      const total = systemTime + userTime
      const last = workerLoads.get(worker)
      let load
      let elapsed
      if (last) {
        const { wall: lastWall, total: lastTotal } = last
        elapsed = wall - lastWall
        const usage = total - lastTotal
        load = Number((usage / (elapsed * 1.0)).toFixed(3))
        updatedCPULoad = true
      }
      const result = { wall, systemTime, userTime, total, load, elapsed }
      log.silly(`Computed worker-${worker.pid} CPU usage`, result)
      workerLoads.set(worker, result)
    }
    if (updatedCPULoad) {
      return this.emit('updated-resource-usage')
    }
  }
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14

I’m just starting to look through all of the documentation. Great stuff!!! Is there any information regarding how many routers one core/worker can handle or is it all just based upon the 200 - 300 viewers spread across the worker regardless of routers? Or is it 200 - 300 viewers per router?

15

Thank you for this sample code on measuring load %!