Re: ImageJ number of cores setting and hyperthreading

Posted by Michael Schmid on May 28, 2015; 8:40am
URL: http://imagej.273.s1.nabble.com/ImageJ-number-of-cores-setting-and-hyperthreading-tp5012964p5012965.html

Hi Christophe,

ImageJ does benefit from hyperthreading.
On my dual-core i5 processor a median filter with radius 10 on a 1024*1024 noise image needs about
  1.5 seconds with 2 threads
  1.0 seconds with 4 threads.

Hyperthreading means that the processor core works on the other thread while it waits for data to be fetched from memory. So you won't see much difference for very small images where all data fit into the cache, but you will get a speed gain for larger images.

Of course, functions or plugins benefit only if they use parallelization. E.g. you won't see a difference for 'Find Maxima', which uses a single thread.

Michael
________________________________________________________________
On May 28, 2015, at 10:02, Christophe Leterrier wrote:

> Hi,
>
> I just got a new laptop with an i7 dual core processor that supports
> hyperthreading. Should I set the number of cores in the ImageJ options to 2
> or 4? In other words does ImageJ benefit from hyperthreading?
>
> Thanks for the help,
>
> Christophe
>
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