Efficient way to use DVR in DQMH modules

[AdarshaPakala]

Ozfarmboy:

Is the constant allocation/deallocation of memory occurring because DVRs are being constantly created/destroyed going to create a determinism issue?  I am think especially for RT here

I had the similar question, What is the memory allocation/deallocation overheads in very frequent DVR create and destroy option(lets say every 50mS) for 24x7 running application?

Thank you

[TiTou]

One additional suggestion for you, in case the data type you stream changes over time, you can typecast the DVR ref into a U32 to make it "embedded-data-type agnostic".

If you do that, when you typecast back from U32 to DVR ref, place the "create DVR" primitive in a disable struct and the data type out of the disable struct 😉

[drjdpowell]

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@TiTou wrote:

One additional suggestion for you, in case the data type you stream changes over time, you can typecast the DVR ref into a U32 to make it "embedded-data-type agnostic".

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Putting the DVR in a Variant is a safer way to do this, in that you wont crash the program if you cast to the wrong datatype (you'll get an error instead).

[TiTou]

...and I was wrong to think that the to-variant + variant-to-data would take longer to execute, it's the same!

I hope LabVIEW will find other ways to crash 😮

[AdarshaPakala]

What is the memory allocation/deallocation overheads in very frequent DVR create and destroy option(lets say every 50mS) for 24x7 running application?

Any thoughts on this?

Between, Thank you for all your replies, its all great information.

Thank you

[drjdpowell]

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@AdarshaPakala wrote:

What is the memory allocation/deallocation overheads in very frequent DVR create and destroy option(lets say every 50mS) for 24x7 running application?

Any thoughts on this?

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My thought is to wonder why you haven't just measured DVR overhead with a simple test VI.  Make and destroy 10,000 DVRs per second and run that overnight.

[AdarshaPakala]

I already did that. I was wondering, I would get more information, if some one already had experienced with bigger application in this scenarios. The behaviour could be different in bigger applications when there is a lot of thread switching, thermal managing/throttling,  large memory management and etc are happening.

[drjdpowell]

So you are asking if anyone with experience using DVRs in this way has had any problems.  That is a better question.