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Could someone from Vienna suggest how many threads to use.
Last post Sat, Jun 08 2013 by Chris T, 12 replies.
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Posted on Thu, Jun 16 2011 06:56
by philco
Joined on Tue, Nov 24 2009, Posts 162

I'd like to hear this answer from someone working for Vienna. There seems to be some confusion.

I'm now running VEP and PToolsHD 9.3 on the same Intel 8 Core Mac Pro. (No slave)

Please advise:

1 How many cores to alot to ProTools and threads to VEP if I'm running these 2 different scenarios…

a)  One 32 bit server (VEP Threads = ?  PTCores =?)

b) One 32 bit server and one 64 bit server (VEP 32 bit threads = ?  VEP 64 bit threads = ?  PTools Cores = ?)

Just to be sure and never have to worry about this again.


Posted on Thu, Jun 16 2011 09:31
by marnix
Joined on Tue, Mar 16 2004, Vienna, Posts 1006

Hi philco,


Unfortunately, there is no absolute answer to your question, as this depends so much on your individual setup and requirements.


As a general rule of thumb, please find below a quote from page 7 of the User Manual:


"Audio Preferences: You may change the number of used threads in the Multiprocessing drop-down menu in real-time, and each Vienna Ensemble PRO instance will use the specified number of process threads. So 1 instance on an 8 core computer should use 8 threads, 2 instances should use 4 threads, and so forth. Ideally you should have as few threads as possible. If you're also running your host sequencer on the same system as the running instances, it might be wise to reserve a core for it.

To keep it simple, set the amount of threads to your amount of cores. If you run into performance issues, lower the amount of threads.



A note on Multiprocessing

There are some general guidelines to follow when using Vienna Ensemble Pro on a system with multiple cores. The general rule to follow is that the optimal number of threads on a system should be equal to the number of virtual cores present.

Vienna Ensemble Pro, like most other hosts today, offers multi-threading. This means that it runs instruments and plug-ins in parallel using several different threads, which allows to utilize several cores on the system. Vienna Ensemble Pro Server will generally perform best when running as few instances as possible. With the VST3 or RTAS plugin, this is possible to achieve by increasing the number of midi ports per instance (see below). Using the AU or VST2 plugins, you might be required to run several instances to work around the 16-MIDI-channel limitation of these standards.

If you are running a sequencer on the same machine as Vienna Ensemble Pro, you could lower the number of threads for Vienna Ensemble Pro, to represent the estimated load of Vienna Ensemble Pro versus the load of your sequencer. In a system with 8 virtual cores and an estimated even load between sequencer and Vienna Ensemble Pro, a good starting point would be to set Vienna Ensemble Pro to 4 threads (if running a single instance). When running more than one instance of Vienna Ensemble Pro, the number of threads per instance should be lowered accordingly.

Certain plugins, such as Native Instruments Kontakt, also offer the possibility of multithreading, which may complicate things further. If using Vienna Ensemble Pro to host such a multitimbral plugin exclusively in one instance, it might give better performance to turn on multiprocessing in Kontakt while keeping a low thread count (1-2) for Vienna Ensemble Pro."


Hope that helps!


Best, Marnix

Posted on Thu, Jun 16 2011 10:54
by philco
Joined on Tue, Nov 24 2009, Posts 162

Thanks so much. That really helps.

This should be a sticky somewhere on the forum so people can refer to it.

Posted on Thu, Jun 16 2011 16:44
by Arceo
Joined on Tue, Sep 28 2010, Posts 61
marnix wrote:
Vienna Ensemble Pro Server will generally perform best when running as few instances as possible. With the VST3 or RTAS plugin

So, can we poor AU users have a little hope that sometimes (in the near future) the sun will shine on us and we'll be able to deal with more than 16 midi channels per instance or (being the AU's specs limited to 16 midi channels) we will never see the light and we will be forced to open dozens of instances for orchestral projects?

Posted on Thu, Jun 16 2011 17:42
by mohurwitzmusic
Joined on Tue, Sep 07 2010, Posts 297
I was wondering-- isn't it possible to use Mac OS X's built in MIDI network capabilities to send the MIDI info, and use VEP only for the audio return? This would circumvent the 16 channel limitation. When I tried this I got a warning that said something like "Using OS X's MIDI network alongside VEP is an experimental feature and may not work properly". Indeed it didn't. Any chance that this will be a feature in the next version of VEP?
Lemur touch controllers for composers and music producers.
Posted on Tue, Sep 11 2012 09:39
by flashman
Joined on Sun, Mar 20 2005, Posts 141

+ 1 on making that a sticky

A workaround to the midi device limit is to use Midi Over Lan as external MIDI. The you can run as many ports as you like on a single insgtance of VSL EP. But let's hope for a solution soon from pple  

Posted on Tue, Sep 11 2012 09:58
by Karel
Joined on Mon, Jan 19 2009, Belgium, Posts 2173

VE Pro 5 has the Multiport layer for Logic (version 9.1.7 and up), as well as the Event Input plugin to circumvent the single MIDI input port limitation. I'd recommend going for the Multiport layer, which is mentioned in the manual on page 37.

Karel Bassez
Software Engineer
Vienna Symphonic Library
Posted on Thu, Sep 20 2012 18:54
by VlnComposer
Joined on Wed, Jan 25 2012, Posts 1

This is all seems to be very helpful information - but i am just curious. . . .

It says above to set the number of threads you have to the number of cores you have. So I am wondering, are you referring to the number of cores on the Host Sequencer machine? Or the number of cores on the Slave machine running Vienna Ensemble Pro?

Any insight to this would be extremely helpful. Thanks!
Posted on Thu, Sep 20 2012 19:02
by flashman
Joined on Sun, Mar 20 2005, Posts 141

I'm pretty sure it must be the slave but Karel is the guru on al this stuff!

Posted on Fri, Sep 21 2012 04:09
by steff3
Joined on Thu, Nov 13 2003, Posts 268

another question - is cores referring to physical cores only or to virtual cores (e.g. i7)?


Posted on Fri, Sep 21 2012 08:36
by MS
Joined on Wed, Feb 19 2003, Vienna, Austria, Posts 1762

Q: Are thread settings important for master or slave?

A: Thread settings apply to the processing slave. Master (Server Interface Plugin) is unaffected by thread settings in Server.

Q: Should number of threads match physical cores or virtual cores?

A: Virtual cores.

Martin Saleteg
Software Developer
Vienna Symphonic Library GmbH
Posted on Sat, Jun 08 2013 19:53
by Chris T
Joined on Fri, Mar 23 2012, Posts 40
I have a Mac Mini 5,2, Intel Core i7 - 2.7GHz, 2 Cores. 16GB of RAM

I'm running it as a slave to my Mac Pro (running DP8). If I have say 2 VE Pro instances in my Metaframe, each is FULL of big sample libraries in large Kontakt 5 multis. How many Threads should I have selected? And what if I have 3 instances loaded?....

Also, I turned off Kontakt Mem Server AND Kontakt Hyperthreading (leaving this to VE Pro). Is this ok?...

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