topic We would need a lot more in Intel® Moderncode for Parallel Architectures

Dramatic Performance Increase - Intel Hyperthreading

Marjan_P_ — Fri, 24 Jul 2015 13:20:00 GMT

Hi,

In Task Manager I was able to see in the lower left corner HT stepping:1->2->3 (these numbers were changing in real time while application was executing) This was right next to CPU usage:%, passed time : nn, Physical memory. Application was really aware of Hyperhreading and was utilizing it. After reformat I cannot restore this magic performance boost.

System:

Intel processor (i3 3220)

Windows 8 Single Language.

I see that OS is HT aware, but it seems that application after reformat is no longer aware or OS is not providing that information for the application.

I would appreciate further help.

We would need a lot more

TimP — Fri, 24 Jul 2015 14:55:52 GMT

We would need a lot more information to make specific comments.

Several of us observed optimum performance with win8.x in some situations by setting 3 threads or Cilk workers on the dual core HT CPU. Under Intel OpenMP library, I generally get best result with 2 threads running on separate cores.

By reformat, do you mean you cleaned the disk and re-installed Windows? Does it still report the 2 cores and 4 logicals on Task Manager Perforrmance view?

Tim,

Marjan_P_ — Fri, 24 Jul 2015 15:34:21 GMT

Tim,

It has 4 logicals in Task Manager. However there is no more that performance boost. HT stepping info is no longer in lower left corner of the Task Manager. Yes I reformatted and install windows. Also professionals from whom I bought the PC restored everything as it was when I purchased it and still nothing.

One important thing:

When I bought that PC on first turn on I had to enter Windows Serial Number, following user name and password (personalization). I typed password fast so I made a mistake. Then I needed somehow to recover password/account. So on the other laptop with Vista (MSI, Intel Centrino processor) on it I downloaded some Windows Password Recovery. I made bootable USB using this program. Then I booted into USB on PC and made new account. I don't know what else could be. This might unlocked that real time HT stepping feature. It perhaps added/unlocked new drivers/features. I had a lot black screens going around after creating new account.

Those numbers from the HT stepping: 1->2->3 were changing automatically (I supposed that it was processor affinity change)

Difference is dramatic (100-200% increase) in terms of responsiveness and overall user experience when this works.

I don't know how to optimize

Marjan_P_ — Fri, 24 Jul 2015 20:40:53 GMT

I don't know how to optimize OS/cpu for multithreading and hyperthreading. I need help for that. Just simple settings in BIOS and seeing 4 logical/2 cores is not enough for application to become aware of HT. Some core optimization in Windows is needed.

I would highly appreciate help on this.

Is there any way to optimize

Marjan_P_ — Sun, 16 Aug 2015 02:17:49 GMT

Is there any way to optimize threading under windows?