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VEPRO, CPU and instances
Last post Tue, Mar 02 2021 by Dewdman42, 7 replies.
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Posted on Sun, Feb 28 2021 13:41
by PaoloT
Joined on Tue, Dec 27 2016, Posts 974

Hi,

I’m trying to distribute the instruments so that their CPU requests are balanced between instances.

What I can't understand is if an instance with little activity will continue to co some CPU time. For example, if one instance contains strings, and they are consuming a lot of CPU, and another only contains a xylophone playing a couple notes, will the instance containing the xylophone consume as much CPU as the one containing the strings?

Paolo

Posted on Sun, Feb 28 2021 17:46
by Dewdman42
Joined on Tue, Feb 27 2018, Park City, Utah, Posts 657
Originally Posted by: PaoloT Go to Quoted Post
Hi,
I’m trying to distribute the instruments so that their CPU requests are balanced between instances.
What I can't understand is if an instance with little activity will continue to co someCPU time. For example, if one instance contains strings, and they are consuming a lot of CPU, and another only contains a xylophoneplaying a couple notes, will the instance containing thexylophone consume as much CPU as the one containing the strings?
Paolo


I think each instance will only use as much cpu as the plugins actually need. The only question is about thread allocation. If you have a lower number of threads per instance, then you could more quickly get drop outs from a busy instance.
5,1 MacPro 12core X 3.46ghz, 128gb ram, RX580 video, OSX Catalina on OpenCore, VSL (almost everything), LogicPro, Cubase10, StudioOne, DP9, Reaper, Dorico, Finale, MuseScore, Notion6, EW Hollywood Orch, Kirk Hunter, GPO, much more..
Posted on Sun, Feb 28 2021 17:50
by PaoloT
Joined on Tue, Dec 27 2016, Posts 974

I'll try to put things into context. In building my template of orchestral sounds, I want to distribute the instruments between the instances, so that VEPRO can allocate my CPU threads in a balanced way.

For example, I've seen that the VI Orchestral Strings can live well in a single instance, with three CPU threads per instance allocated by VEPRO. Since all the other instances will use three threads, I have to assign them the instruments following two criteria:

1) the instruments in the instance will not overload the CPU;
2) the instruments in the instance will be of the same type, for better organization.

So, I've seen that all woodwinds can live in a single instance. All classic brass have their instance. Dimension Brass their own. Each Dimension Strings section has its own instance.

Percussion should have their own instance. But I'm in doubt where to allocate mallets. They are percussions, played by percussionists, but follow different rules than most of the other percussions (pitched like timpani, or unpitched as snare drums). They are crossing the boundaries between percussion and keyboards. So, I'm temped to keep them together with keyboards and harps in a separate instance.

This is, however, sort of forcing the nature of the mallets. So much, that I'm tempted to leave them in their own instance. And so, maybe for the harps.

But would this make the CPU cycles assigned to their instances go wasted?

Paolo

Posted on Sun, Feb 28 2021 21:17
by Dewdman42
Joined on Tue, Feb 27 2018, Park City, Utah, Posts 657

cpu "cycles" don't really get wasted by inactive instances.   They are inactive and aren't using any CPU core "cycles".

its not an exact science and depends so much on your hardware and your music too.  I recommend you structure your instances the way that makes sense for you to work and don't obsess over trying to optimize their core use.  VePro has really good thread processing, honestly, I mostly just leave my thread setting to maybe 80-90% of 2x the number of cores....and I never worry about it.  If in a particular project you find you're having some issues, then you can play with the thread setting.  It really depends so much on many factors and there is a lot of misunderstanding about the difference between "threads" and "cores".

 The only thing is that if you have a low thread-per-instance setting, then if you create an instance with a lot of instrument channels that are all busy...that particular instance will be constrained in what it can accomplish with only a few threads, and if it can't keep up with the audio buffer, you'd experience audio dropouts from that instance.

I think its best to keep things simple.  Organize your instances in a way that makes sense for you to work, then play with the thread setting if and when you have any cpu related drop outs.

Nerd Alert

This topic can get complicated.  Truthfully, we customers don't know the exact internals of VePro how thread allocation is done, but keep in mind that "threads" does not equate exactly to "cores".  "Cores" are a hardware component, of which there is a fixed number in your computer.  At any given instant, those N number of cores are working separately, in parallel.  Using CPU cycles, so to speak.

"Threads" are a software concept.  When a program can do certain work in parallel to other work, they can create a kind of software job called a "thread".  The program will create any number of threads, even more than the actual number of hardware cores, ...and then those various threads will take turns using the fixed number of hardware cores.  

And at any given instance your computer has dozens of programs that are actually running, some of them with multiple threads too, which means you could have something like 50-100 total software threads happening across all the programs running on your system...and they are all taking turns using the fixed number of hardware cores.  Some threads are idle!  When they are idle they aren't using much CPU, but their mere existence means that the OS will have to take a little time periodically to see if they have work to do...so yea, there is a little bit overhead associated with each thread, even when its idle, that' why we don't just create a buzzillion threads.  You want plenty of threads, but not so many that the overhead starts to harm performance.

So anyway back to your original question, idle threads are not so much of an issue, they are not using up much cpu cycles really.  

The challenge is more about making sure that none of the N number of hardware cores are ever sitting around idle.  You want to make sure that there plenty of threads between all the VePro instances, so that at any given instance, all N cores are working as hard as possible, none are sitting around waiting.  If you have too few threads, then the situation could happen with a few peaked cores...and other cores doing not much.  The peaked cores in that case will give audio drop outs.

But the problem here is if you have a busy instance that needs more than 3 threads to work efficiently, maybe because it has 10 channels in it (where each one of those channels could potentially be using its own thread to maximize the core usage).  If you have the setting at 3, but one instance is using 10 channels, then those 10 channels have to take turns using 3 threads, which in turn are taking turns on the cores.  If the music came to a place where that was the only instance making sound, it would definitely be under-utilizing the cores.

Each VePro instance is like a completely separate VePro server in a way.  Its sharing all the cores, along with other programs too.  So how many threads should each of those instances allocated such that it won't under utilize the cores...but also won't create too much overhead with too many threads.  Too many active threads just get in their own way while they take turns using the cores.

It depends a lot on your music too.  if you will always have a balanced playback where all (or at least several) of your instances are playing approximately the same number of channels...with notes turning into sound, always approximately the same time, then yes a low thread count would be more ideal.  However, if you tend to have music which might hit one instance hard for a while, then another instance hard for a while, etc..then you'd want a larger thread setting.  it just depends on you and your music and how many cores you have.

I personally think it makes more sense to just organize your instances the way that makes sense for your work flow and don't obsess too much about the threading stuff.  Play around with the thread setting if you like, might need to be different for different projects because of the way the music will be arranged will change how the instances use it.

If that is too much to worry about, then that is why I prefer generally one of two scenarios, either one super huge instance with all my instruments in one instance and thread setting as high as possible.

or..  One instrument per instance, with a thread setting of 2.

when you go to the in-between instance sizing, that's when the answer is a big fat "it depends".

5,1 MacPro 12core X 3.46ghz, 128gb ram, RX580 video, OSX Catalina on OpenCore, VSL (almost everything), LogicPro, Cubase10, StudioOne, DP9, Reaper, Dorico, Finale, MuseScore, Notion6, EW Hollywood Orch, Kirk Hunter, GPO, much more..
Posted on Sun, Feb 28 2021 21:49
by PaoloT
Joined on Tue, Dec 27 2016, Posts 974

Dewdman, detailed but clear as usual!

So, what counts seems to be to reserve enough threads to the most CPU consuming instance. All the others can be lighter, without risking to lose anything of the total power of the computer.

I'll go for an as modular organization as I find comfortable, without grouping too many incompatible things together.

Paolo

Posted on Tue, Mar 02 2021 15:46
by William
Joined on Sun, Nov 24 2002, USA, Posts 5618

Dewdman, that is impressively nerdish!   

It is striking how my oddball system does not encounter so many problems other people seem to have.  I am using VE standalone on a slave, one instance with a large number of channels, and recording audio in a third computer.  So I have a sequencing computer, a VSL playback computer, and an audio recording computer.   This way, one maxes out the computer's power as exclusively as possible for VSL. 

But no one else seems to do that and instead use various DAW setups that consume resources, multiple instances of VE, MIR separate from VE in their DAW, etc. I decided to do this standalone because in the past I had underpowered computers.  Nowadays I don't,  but I still have the same basic setup.  (Partly because the audio recording computer is also for video editing and so it helps for the workflow.)  Maybe VE operating in this "pure" way is more efficient?  But it doesn't have the overloading of CPU etc. that seem to be reported regularly.   

Posted on Tue, Mar 02 2021 16:48
by Dewdman42
Joined on Tue, Feb 27 2018, Park City, Utah, Posts 657

In the context of this discussion your use of one single large vepro instance allows vepro more complete control over thread allocation. Having vepro as a slave in its own computer definitely doesn’t hurt either

5,1 MacPro 12core X 3.46ghz, 128gb ram, RX580 video, OSX Catalina on OpenCore, VSL (almost everything), LogicPro, Cubase10, StudioOne, DP9, Reaper, Dorico, Finale, MuseScore, Notion6, EW Hollywood Orch, Kirk Hunter, GPO, much more..
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