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AnswerRe: problem in line plotting IN VC++ Pin
Cedric Moonen8-Feb-11 20:07
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QuestionList control in MFC Pin
Nikesh Jagtap8-Feb-11 17:24
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AnswerRe: List control in MFC Pin
Hans Dietrich8-Feb-11 18:29
mentorHans Dietrich8-Feb-11 18:29 
AnswerRe: List control in MFC Pin
_AnsHUMAN_ 8-Feb-11 18:34
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QuestionLogical Processors Vs Physical Processors Pin
Ahmed Charfeddine8-Feb-11 10:28
Ahmed Charfeddine8-Feb-11 10:28 
AnswerRe: Logical Processors Vs Physical Processors [modified] Pin
Luc Pattyn8-Feb-11 11:04
sitebuilderLuc Pattyn8-Feb-11 11:04 
[ADDED]
What follows is based on the assumption a lot of homogeneous work, mainly calculations, is to be performed and can be organized in a (small) number of threads without needing lots of synchronization. It would not apply to inhomogeneous operations, say some threads performing calculations, others disk I/O, others network I/O, etc.
[/ADDED]

In general I would base my considerations on the number of threads that can be active at the same time; this would ignore the physical aspects involved such as separate packaging, multi-core, hyper-threading... So the number of (logical) processors returned by GetSystemInfo() is what I would use.

The one exception would be applications where performance is dominated by cache efficiency; if so, what really matters is the number of separate level-2 caches available, which could be better approximated by the number of physical processors.

Hint: what would be keeping you from trying both? As your threading code would be dynamic anyway, why not perform an experiment? or even make it automatic: run with N threads for a while, then try 2*N and see if that is an improvement, then decide.

Smile | :)
Luc Pattyn [Forum Guidelines] [My Articles] Nil Volentibus Arduum
Please use <PRE> tags for code snippets, they preserve indentation, improve readability, and make me actually look at the code.

modified on Tuesday, February 8, 2011 5:10 PM

GeneralRe: Logical Processors Vs Physical Processors Pin
Ahmed Charfeddine8-Feb-11 23:00
Ahmed Charfeddine8-Feb-11 23:00 
AnswerRe: Logical Processors Vs Physical Processors Pin
Luc Pattyn8-Feb-11 23:14
sitebuilderLuc Pattyn8-Feb-11 23:14 
GeneralRe: Logical Processors Vs Physical Processors Pin
Ahmed Charfeddine8-Feb-11 23:27
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QuestionSynchronization Pin
Andry_st8-Feb-11 10:17
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AnswerRe: Synchronization Pin
Ahmed Charfeddine8-Feb-11 10:29
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Maximilien8-Feb-11 10:30
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GeneralRe: Synchronization Pin
Andry_st9-Feb-11 0:39
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QuestionShell's context menu items are all gray [modified] Pin
David Crow8-Feb-11 4:33
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QuestionRe: Shell's context menu items are all gray Pin
Maximilien8-Feb-11 5:06
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David Crow8-Feb-11 5:11
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Maximilien8-Feb-11 6:47
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GeneralRe: Shell's context menu items are all gray Pin
David Crow8-Feb-11 6:51
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QuestionIncremental search method for CEditview or CRicheditView Pin
ganesh.dp8-Feb-11 1:29
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AnswerRe: Incremental search method for CEditview or CRicheditView Pin
Niklas L8-Feb-11 2:52
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QuestionResizing controls as per screen resolution Pin
ddgalande8-Feb-11 1:27
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AnswerRe: Resizing controls as per screen resolution Pin
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