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Re: PAE or not PAE?

Le 13/03/2018 à 04:57, Joe Pfeiffer a écrit :
Gene Heskett <gheskett@xxxxxxxxxxx> writes:

Both pae and hyperthreading take time, hyperthreading quite a bit more
than pae. With hyperthreading, to switch to the 2nd task, takes a
complete processor state stored on the stack, the stack pointer reloaded
to point at the image of the 2nd task, then pull the full register dump
for task 2 back into the processor.

What you describe is software multi-threading/multi-tasking, not hyperthreading.

This doesn't correlate with my understanding of the process.  My
understanding, and every block diagram I've seen of a processor capable
of hyperthreading, has a separate set of architectural registers for
every thread.

I agree.

The processor does need to start refilling the pipeline
on a thread switch

I don't think so, because IIUC there is not thread switch. Both threads instructions can be executed in parallel as long as they do not use the same resource.

I will agree that it increases the unpredictability of execution time,

This is the endless trade-off between thoughput and response time.