Why factoring is single-core designed?

[otutusaus]

Originally Posted by Mini-Geek

if you want to experiment, tell Prime95 to put that worker on a specific core and see what happens to the speed and what appears in the task manager)

Originally Posted by CRGreathouse

It's switching between cores. If you like you can set processor affinity for the thread and see if there's a performance difference; I doubt it.

Thanks for your patience and suggestions, I will definitely try that.

[Uncwilly]

Originally Posted by otutusaus

Mr. Silverman, I started posting less than a week ago and I am still getting familiar....
I regret having to read posts like yours. Please be more respectful and tolerant with other people's ignorance.

That is Bob. Ignorance is one thing, but if he sees an unwillingness to learn, he gets testy.

[davieddy]

Originally Posted by R.D. Silverman

If you want to be argumentative, go somewhere else.

On the contrary: if he's looking for an argument, he's
come to the right place.
Or is this abuse?

David

[R.D. Silverman]

Originally Posted by Uncwilly

That is Bob. Ignorance is one thing, but if he sees an unwillingness to learn, he gets testy.

The issue is not ignorance. He asked a reasonable question.

But after he was given a response from several different posters
he still continued to argue about it.

[otutusaus]

I understood the fact that it is more efficient to run FT in a single core than to divide the job between cores. All answers were clear about that. I wasn't arguing about that anymore. This is settled. Single core is best. Thank you for your explanations.

What I was stating later is that it looks as if the FT in Prime95 is running shared between cores (according to what I see the Windows Task Manager).

Anyway, I've run FT tests using different settings (Smart assignment in 1 thread/2 cores, Run on any CPU in 1 thread/2 cores, Run on any CPU in 1 thread per core, or as CPU #1 in 1 thread) and all timings are the same.

[Uncwilly]

Originally Posted by R.D. Silverman

The issue is not ignorance. He asked a reasonable question.

But after he was given a response from several different posters
he still continued to argue about it.

That does not go against what I said.

[markr]

Originally Posted by otutusaus

I understood the fact that it is more efficient to run FT in a single core than to divide the job between cores. All answers were clear about that. I wasn't arguing about that anymore. This is settled. Single core is best. Thank you for your explanations.

What I was stating later is that it looks as if the FT in Prime95 is running shared between cores (according to what I see the Windows Task Manager).

It may look a bit like it in Task Manager, because Task Manager would be doing some time-averaging. What you are seeing is prime95 being switched between cores (as CRGreathouse said earlier). This means it runs on one core for a time, then is moved to another, ..., at the whim of the OS. From our (human) perspective this can happen very quickly. This is not the same thing as multithreading, where an application runs on two or more cores at the exact same time.

Disclaimer: Regarding computers, I am an untrained lay-person. (IANAL equivalent.) Doubtless there are exceptions & more precise definitions than my essay.

[davieddy]

Originally Posted by R.D. Silverman

The issue is not ignorance. He asked a reasonable question.

But after he was given a response from several different posters
he still continued to argue about it.

God you are such a reasonable man.

David

PS If you need any more ammo, try my latest post
in the music thread.

[ET_]

Originally Posted by otutusaus

I understood the fact that it is more efficient to run FT in a single core than to divide the job between cores. All answers were clear about that. I wasn't arguing about that anymore. This is settled. Single core is best. Thank you for your explanations.

What I was stating later is that it looks as if the FT in Prime95 is running shared between cores (according to what I see the Windows Task Manager).

Anyway, I've run FT tests using different settings (Smart assignment in 1 thread/2 cores, Run on any CPU in 1 thread/2 cores, Run on any CPU in 1 thread per core, or as CPU #1 in 1 thread) and all timings are the same.

You may try Wintop to check timings on different threads.

Luigi

[Vato]

Originally Posted by markr

This means it runs on one core for a time, then is moved to another, ..., at the whim of the OS.

This is correct, and is true on most* OS and most* hardware.

The reason is that it makes for more even heat generation/dissipation within the CPU => cooler => more reliable => longer lifetime.

* most = all, in my personal experience, unless affinity has be used to override this.

[cheesehead]

Originally Posted by Vato

The reason is that it makes for more even heat generation/dissipation within the CPU => cooler => more reliable => longer lifetime.

Thanks for pointing this out. It's something I'd hardly ever consider.

Originally Posted by Vato

* most = all, in my personal experience, unless affinity has be used to override this.

Does that mean that using affinity to assign particular GIMPS tasks to particular cores could, theoretically, reduce CPU reliability and/or lifetime (compared to the case where the OS periodically rotated tasks among cores) if some of those tasks were more CPU-intensive than others?