FFMPEG using a single socket

[ServerGuy 24]

While waiting for chapter image extraction i noticed that FFMPEG appears to only be using a single socket on my server. Is there a parameter that needs modified to use both sockets or is this by design?

 

The image below shows CPU utilization per core. All other resources at the time show no bottlenecks. (e.g. Disk queue stays less than .02, memory utilization stays around 11%)

 

[Luke 42092]

Hi there, can we look at log file examples? thanks.

[ServerGuy 24]

No problem, I shared the log on my Google Drive and will PM you the link

[Luke 42092]

Adding @@softworkz for his opinions. Thanks.

[softworkz 5078]

While waiting for chapter image extraction i noticed that FFMPEG appears to only be using a single socket on my server. Is there a parameter that needs modified to use both sockets or is this by design?

 

The image below shows CPU utilization per core. All other resources at the time show no bottlenecks. (e.g. Disk queue stays less than .02, memory utilization stays around 11%)

 

(The image shows CPU utilization by logical processor, not by core.)

 

Following calculation:

• You have 2 CPUs each having 8 cores which support hyperthreading

  .

• That makes 16 cores and 32 logical processors altogether

  .

• The overall CPU utilization is 14%

  Let's account 12% for being used by Emby for image extraction

  12% * 32 = 3.84 ==> that's about 4

 

Which means that Emby is using 4 "threads" for the operation

("threads" must be used careful as it can have different meanings)

 

If things were simple, then you would see 4 logical processors at 100% and the others in the area of 0%.

The reason why you see this load distributed over 16 logical processors is CPU design.

One aspect that everybody can understand is thermal behavior and the intention to ensure consistent spreading of heat accross the die.

 

 

As to your qestion about the second socket CPU: This CPU is kept in power saving mode as it is not needed and it could be of not help for a task that requires only 4 logical processors.

[ServerGuy 24]

In shifting my question slightly, are there parameters I can change that will utilize more of my available resources for this task? Ill start a separate thread for overall recommendations.

 

What brought about the question was that after the 4.0 update, my CPU utilization remained at that level for 19 hours while performing chapter image extraction. My hope is that by spreading out the load better I can reduce that time.

[softworkz 5078]

In shifting my question slightly, are there parameters I can change that will utilize more of my available resources for this task? Ill start a separate thread for overall recommendations.

 

What brought about the question was that after the 4.0 update, my CPU utilization remained at that level for 19 hours while performing chapter image extraction. My hope is that by spreading out the load better I can reduce that time.

 

 

Just today I had written in another thread about parallelization:

 

It's just that multi-threading does not automatically mean that an infinite number of threads can be involved.

 

There are limits to parallelization which are depending on the actual job to do.

 

In many cases there's an optimum and using more threads would make things even slower.

 

That's why it's usually(!) not an "ffmpeg limitation" but a parallelization limit of the algorithms involved.

 

 

Now, what would be possible in theory of course, is executing multiple image extractions in parallel.

 

We're not doing this for two reasons:

1. It's only done once for each file. It might have taken 19 hours for you, but from now on it will only happen for newly added videos
2. This kind of task is meant to run in the background.

   That means that it shouldn't affect user experience.

   If we would max out your server resources, your server would be unusable for normal operation