CFD Online Logo CFD Online URL
Home > Forums > Software User Forums > OpenFOAM

OpenFOAM + Hyperthreading

Register Blogs Members List Search Today's Posts Mark Forums Read

Like Tree2Likes
  • 2 Post By Giuliano69

LinkBack Thread Tools Search this Thread Display Modes
Old   May 3, 2012, 21:40
Default OpenFOAM + Hyperthreading
New Member
Join Date: Mar 2012
Posts: 10
Rep Power: 10
Mister_K is on a distinguished road
I asked my engineering supervisor whether Intel's hyperthreading technology benefits OpenFOAM computing, which to my surprise it does not.

He explained because there are only 4 physical cores doing work, and tasks will just bounce between either the physical or virtual core pair.

Is this correct?
Mister_K is offline   Reply With Quote

Old   May 4, 2012, 00:55
Senior Member
linnemann's Avatar
Niels Nielsen
Join Date: Mar 2009
Location: NJ - Denmark
Posts: 526
Rep Power: 23
linnemann will become famous soon enough
yes that is correct

PS. I do not do personal support, so please post in the forums.
linnemann is offline   Reply With Quote

Old   May 4, 2012, 02:15
New Member
Join Date: Mar 2012
Posts: 10
Rep Power: 10
Mister_K is on a distinguished road
Thanks for the reply
Mister_K is offline   Reply With Quote

Old   May 26, 2012, 14:33
New Member
Giuliano Lotta
Join Date: May 2012
Posts: 12
Rep Power: 10
Giuliano69 is on a distinguished road
You came to and old debate, that face AMD opteron multi-core, against Intel multi thread....You can find many 3d on this subj on this forum...

Inter HT CPU have 2 thread per core.
The MAIN point is that each core can have just ONE single thread working at any time.
Where is the deal ?
IF a memory I/O is required, when the thread is working for fetching the data, the other thread can proceed on the same core.

In general terms, this lead to a performance improvement.(approx 20%-30%)

BUT, coming to HPC on CFD, another consideration becomes important: Memory access/bandwidth consideration.
if the memory accessed by the thread are on "different" memory area, so that the chace doesn't help, HT on more thread could give performance downgrade, instande of speed up.
It is the case of CFD with a huge cell number.

Even more, dividing the memory bandwidth between more cores/Threads degrade the memory access performance for each single core/thread.
(it's the origin of the debate AMD/Intel: it is better a multi CPU (AMD) or a multi core (Intel) based workstation ?)

You can find interesting result and comparison on a "famous" article:

hope it helps...

randolph and Ramzy1990 like this.
Giuliano69 is offline   Reply With Quote


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
New OpenFOAM Forum Structure jola OpenFOAM 2 October 19, 2011 07:55
Cross-compiling OpenFOAM 1.7.0 on Linux for Windows 32 and 64bits with Mingw-w64 wyldckat OpenFOAM Announcements from Other Sources 3 September 8, 2010 07:25
Modified OpenFOAM Forum Structure and New Mailing-List pete Site News & Announcements 0 June 29, 2009 06:56
64bitrhel5 OF installation instructions mirko OpenFOAM Installation 2 August 12, 2008 19:07
Adventure of fisrst openfoam installation on Ubuntu 710 jussi OpenFOAM Installation 0 April 24, 2008 15:25

All times are GMT -4. The time now is 13:37.