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Old   December 2, 2017, 03:41
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YHY
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Hello everyone,

I have a question about the Hyper-Threading .
When i enable the Hyper-Threading of the workstation with 12 cores and 24 threads, the calculate speed of Converge case slow down compare to disable the Hyper-Threading. So i am confused that why it slow down when the Hyper-Threading is used? Did you met this situation? Is there any solutions? Maybe it is recommended disabled the Hyper-Threading when use Converge?
Thanks for your help!

Sincerely!
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Old   December 2, 2017, 06:58
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Quote:
Originally Posted by YHY View Post
Maybe it is recommended disabled the Hyper-Threading when use Converge?
Hi,

yes, it is recommended to disable HT. With HT, one physical core appears as two processors to the operating system, allowing concurrent scheduling of two processes per core. However, this slows down the processes.

Easy way to say it, virtual cores are not as fast as physical ones, therefore the physical ones have to wait for the results calculated by the virtual ones, because load ballancing assumes equal perfomances.
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Old   December 2, 2017, 07:24
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Originally Posted by MFGT View Post
Hi,

yes, it is recommended to disable HT. With HT, one physical core appears as two processors to the operating system, allowing concurrent scheduling of two processes per core. However, this slows down the processes.

Easy way to say it, virtual cores are not as fast as physical ones, therefore the physical ones have to wait for the results calculated by the virtual ones, because load ballancing assumes equal perfomances.
Your answer is very helpful. Thank you very much for your help!
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Old   July 12, 2018, 23:01
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Hi,

Where is the option to disable or use HT in Ansys Fluent?

Thank you.
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Old   July 13, 2018, 01:46
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I think that enable/disable HT can only be done in BIOS menu, not for specific applications.
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Old   July 13, 2018, 03:00
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I think that enable/disable HT can only be done in BIOS menu, not for specific applications.
Thank you.
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Old   August 14, 2018, 14:03
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Hyperthreading is useful for simulations involving spray parcels, and can be upto 20-25% faster than when using physical cores, but this gain in speed is only during the duration of spray. Make sure you use the command '--t' in cmd while starting simulation to enable hyper-threading in converge. I dont know about the impact of this in a cluster based computer but this certainly is effective in workstations.
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