[Imstk-developers] high-speed thread in iMSTK

[Zhaohui Xia]

Hi Sreekanth,

 

Theoretically, we can write and read force and other information to the haptic device via their API. Why iMSTK didn’t provide this interface? 60-70HZ is not a smooth force even it is a zeroth-order hold, we need to consider the force filter in the high-speed thread.

 

Thanks,

Zhaohui

From: Sreekanth Arikatla [mailto:sreekanth.arikatla at kitware.com] 
Sent: 2017年6月8日 16:17
To: Zhaohui Xia <unihui at gmail.com>
Cc: Andinet Enquobahrie <andinet.enqu at kitware.com>; imstk-developers at imstk.org
Subject: Re: [Imstk-developers] high-speed thread in iMSTK

 

Hi Zhaohui,

                  I'm guessing you are using phantom omni. If so yes, it has its own servo thread that starts after hdStartScheduler() call. Its rate is much higher and can be set with hdSetSchedulerRate() but is left to the default value in iMSTK. The forces are still updated at 60-70 Hz but applied in zeroth-order hold fashion.

 

Unfortunately the debug mode runs much slower. I'm not aware of any other way than setting the VS flags for speed <https://msdn.microsoft.com/en-us/library/k1ack8f1.aspx> . You may also try (if possible) using small mesh to debug code and run actual mesh in release. 

 

On Thu, Jun 8, 2017 at 3:33 PM, Zhaohui Xia <unihui at gmail.com <mailto:unihui at gmail.com> > wrote:

Hi Andinet,

 

I am afraid I made a mistake. The device thread is definitely a high-speed thread. I figure out the issue, because I forget to close something when I change the code in that thread.

 

I think there is no performance bottlenecks currently in the main thread under Release mode (60-70HZ), since the mesh size (1000 vertices) is not very big now.

But under Debug mode, the speed is too slow, it is just 0.16HZ for the same mesh. Do we have any ways to improve it, e.g. changing some settings? It would be very helpful for work if it can run faster.

 

Thanks,

Zhaohui

From: Andinet Enquobahrie [mailto: <mailto:andinet.enqu at kitware.com> andinet.enqu at kitware.com] 
Sent: 2017年6月8日 13:29
To: Zhaohui Xia < <mailto:unihui at gmail.com> unihui at gmail.com>
Cc:  <mailto:imstk-developers at imstk.org> imstk-developers at imstk.org
Subject: Re: [Imstk-developers] high-speed thread in iMSTK

 

Zhaohui

 

Can you profile your code and let us know the key performance bottlenecks in iMSTK?

 

This is something Dr. Des is also interested. We will be exploring ways of accelerating some of the modules.

 

thanks

Andinet

 

 

 

On Thu, Jun 8, 2017 at 12:40 PM, Zhaohui Xia <unihui at gmail.com <mailto:unihui at gmail.com> > wrote:

Hi All,

 

Do we have a high-speed thread (e.g. 1000HZ) in iMSTK? I tried different modules e.g VRPNDeviceServer (device) and SceneMange (main thread), but the maximum frame rates of them are 60-70HZ under Release mode.

I also tried to set the Loopdelay to 0.001 or smaller (from my understand, its default value is 0 should have the fastest speed, but it also 60-70HZ).

 

Thanks,

Zhaohui

-----------------------------------------------------------------------------------------------------------

Zhaohui Xia, Ph.D.
Postdoctoral Research Associate, Center for Modeling, Simulation and Imaging in Medicine (CeMSIM)
Rensselaer Polytechnic Institute


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-- 

Andinet Enquobahrie, Ph.D., MBA
Director of Medical Computing
Kitware, Inc.

http://www.kitware.com

 <tel:%28919%29%20969-6990%20x311> (919) 969-6990 x311

 

 


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-- 

Sreekanth Arikatla, Ph.D.,

Senior R&D Engineer,

 <http://www.kitware.com> Kitware, Inc., Carrboro, NC.

 

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