Processor Scalability and Linux

Marko Vojinovic vvmarko at
Sun Aug 8 19:15:18 UTC 2010

On Sunday, August 08, 2010 19:41:33 Joshua C. wrote:
> How can I judge if a particular _linux_ app will work well with a
> 6-/4-core cpu? What to look for? How does the OS interact with the app
> in allowing it to use the resources? Is the app solely responsible for
> utilizing all the system resources? Are more cores/threads really
> better?

Every particular app needs to be designed and implemented in a way that is 
parallelizable, ie. to use multiple threads. Some apps already do that, some 
don't. Depending on what task a particular app is meant to perform, parallel 
implementation may be trivial, easy, difficult or impossible (even 

If you want to know if app foo is multithreaded, look at the source code. Or 
the documentation. Or ask the developers who made it.

For some apps, it just doesn't make sense to be multithreaded. A typical 
example would be a word processor --- the main thing it does sitting idle and 
waiting for user input. One thread is more than enough. Other things, like 
http server, make very good use of multiple threads.

If you have six cores, it means you can run six independent apps 
simultaneously, each on one core. This is independent of the design of the 
apps themselves, and is certainly better than having only four cores, but not 
very drastically better. So much for the system resources. Everything else is 

HTH, :-)

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