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Re: Debian on Pine64 H64B?

On Tue, Sep 21, 2021 at 05:00:12AM -0400, Gene Heskett wrote:
> No, in fact disabling that is a bios setting done before even installing 
> LinuxCNC. It may make winderz seem to be better, but that context 
> switch, done by the relatively slow bios memory is a performance killer 
> even if the code is stashed in L1 cache. I've 5 i5's of various builds 
> here, and none of them have that enabled even if its not running 
> machinery. This cheap 6 core i5 certainly doesn't need it and its 
> actually running at 800 MHz, but capable of 3.7 GHz. Close to zero heat, 
> all 6 cores are below 32C right now.

The BIOS has nothing to do with context switching.  Hyperthreading doesn't
even do context switching, it has two sets of registers so it can do
free context switching while the other thread is waiting for something.

Hyperthreading's only big problems are that it makes execution speed of
each thread unpredictable and since two threads are sharing a core,
it reduces the performance of single threaded code on that core.

Len Sorensen

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