[fpc-pascal] Single threaded application on multicore CPU

Mattias Gaertner nc-gaertnma at netcologne.de
Wed Jun 22 14:14:01 CEST 2016

On Wed, 22 Jun 2016 07:41:04 -0400
Stephen Chrzanowski <pontiac76 at gmail.com> wrote:

> Everything has a cost.  But swapping CPU threads isn't as costly as a fried
> CPU.  Keeping the CPU cool at all costs is better than having a hotspot on
> the die which COULD damage the heat sink.

On my Linux it does not swap the CPU and I can't find any hard data that
Windows is swapping because of hotspot problems, but I do find many
pages about pinning processes to cores.
Please provide a link for the hotspot claims.

> The computing cost of swapping CPUs is probably close to zero.  Your CPU
> only has so much on-die memory that it has to push things out CONSTANTLY to
> on board RAM, so there may be a time when your CPU (Not the Operating
> System) has zero knowledge of your application.  When your OS takes the
> information back to the CPU, the OS will look at the particularities of CPU
> (Heat, load, in use, etc) and specify which CPU will get the task.

Swapping a process costs about 1000-100000ns on an idle system (only
one busy thread), mostly depending on caches. So even if Windows
would swap a hundred times per second, the overhead would be less than
To make sure, pin your process to a cpu and compare.


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