About 5%.  Been doing it for over a year using a program written in C++ and
operating as a service under Windows.  

Charles Elliott

-----Original Message-----
From: Nicolás Alvarez [mailto:[email protected]] 
Sent: Thursday, March 11, 2010 4:19 PM
To: [email protected]
Cc: <[email protected]>
Subject: Re: [boinc_dev] BOINC Applications Speed-Up by Setting the
Processor Affinity

Every year someone shows up trying to convince everyone that there  
will be a giant speed up if BOINC implements CPU affinity, based on  
theory and not practice. Please try setting CPU affinity manually when  
WUs start, and let us know how much faster they finish.

Large enough performance improvements (measured by experiment) on real  
BOINC apps is more likely to motivate change than citing papers.

Enviado desde mi iPod

El 11/03/2010, a las 14:06, "Charles Elliott" <[email protected]>  
escribió:

> If anyone is interested there is a good explanation for why BOINC
> applications experience a speed-up
>
> when each application is assigned an affinity for one CPU (and by
> implication why it does not work for
>
> single-CPU hyperthreading) here:
>
>
>
> Fedorova, A., S. Blagodurov, et al. (2010). "Managing contention for  
> shared
> resources on multicore
>
> processors." Commun. ACM 53(2): 49-57.
>
>
>
> Essentially, one can infer from the article that the speed-up is due  
> to
> fewer cache misses and
>
> reduced contention for the front-side bus and the memory controller.
>
>
>
>
>
> Charles Elliott
>
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