Hyperthreading

kakrofoon
kakrofoon
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Topic 187987

If you use a hyperthreading PC tell einstein@home to use only one processor; It goes around 5x faster.

[B^S] Paul@home
[B^S] Paul@home
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Hyperthreading

hmm.. slightly faster yes.... 5x faster? I'm not sure about that... certainly not in my experience anyway!

Have you a list of timings? (link to one of your hosts experiencing this?)


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Bruno G. Olsen & ESEA @ greenholt
Bruno G. Olsen ...
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> If you use a hyperthreading

> If you use a hyperthreading PC tell einstein@home to use only one processor;
> It goes around 5x faster.

Seems odd. Last I heard about HT CPUs, they would in fact run a wu a bit faster when using one "CPU", but overall you'd process more wu's by using both.

Jordan Wilberding
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> hmm.. slightly faster

Message 5187 in response to message 5185

> hmm.. slightly faster yes.... 5x faster? I'm not sure about that... certainly
> not in my experience anyway!
>
> Have you a list of timings? (link to one of your hosts experiencing this?)

Well maybe we can just have a few people provide examples? Here is my computer, running at 3.06Ghz with HT as 2 processors:

http://einsteinathome.org/host/20522

It takes me roughly 84,500 to complete two WU's

such things just should not be writ so please destroy this if you wish to live 'tis better in ignorance to dwell than to go screaming into the abyss worse than hell

[B^S] Paul@home
[B^S] Paul@home
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> > It takes me roughly

Message 5188 in response to message 5187

>
> It takes me roughly 84,500 to complete two WU's
>

that is about 24 hours (ish!) per WU, and as you pointed out you are running 2 in that time (running at the same time on HT processor) so that makes an average thruput of about 12 hours per unit while running HT.

Thats in line with my experience.

have you any results for that machine with HT switched on but prefences set to use 1 CPU only?


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Paul D. Buck
Paul D. Buck
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All of the historical tests

All of the historical tests say that the time to complete comes down, but the total throughput is less. So, yes, you do a single work unit faster, but using HT you will take longer on both, but will complete the two before the processor doing them without HT will complete both.

With HT *ON*, the time to complete 2 WU is about 1.5 times the time that the same processor doing ONE work unit with HT *OFF*.

figures are apporximate, your mileage may vary, things are closer than they appear ... see disclaimer for details.

Divide Overflow
Divide Overflow
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> figures are apporximate,

Message 5190 in response to message 5189

> figures are apporximate, your mileage may vary, things are closer than they
> appear ... see href="https://einsteinathome.org/%3Ca%20href%3D"http://boinc-doc.net/site-common/glossary/letter-d.php#disclaimer">http://boinc-doc.net/site-common/glossary/letter-d.php#disclaimer">disclaimer[/url]
> for details.

Keep that kind of talk up and we're going to rename your FAQ the unofficial BOINC Terms and Conditions document!

Ageless
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If you think you can do it

Message 5191 in response to message 5190

If you think you can do it better...

Remember: Starting a Boinc.wikipedia.org page isn't doing it better. ;)

Paul D. Buck
Paul D. Buck
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> > figures are apporximate,

Message 5192 in response to message 5190

> > figures are apporximate, your mileage may vary, things are closer than
> they
> > appear ... see
> href="https://einsteinathome.org/%3Ca%20href%3D"http://boinc-doc.net/site-common/glossary/letter-d.php#disclaimer">http://boinc-doc.net/site-common/glossary/letter-d.php#disclaimer">disclaimer[/url]
> > for details.
>
> Keep that kind of talk up and we're going to rename your FAQ the unofficial
> BOINC Terms and Conditions document!

I been called worse things ...

I am afraid when I saw that one, I could not resist ... one of these days when my sense of humor is in REAL fine shape I am going to go in and add to it ...

Read my "Aside 001" for a response to someones complaint about my humor in the original FAQ documents.

Ageless
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Is that copyrighted, Paul? ;)

Is that copyrighted, Paul? ;)

Divide Overflow
Divide Overflow
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> > Keep that kind of talk up

Message 5194 in response to message 5192

> > Keep that kind of talk up and we're going to rename your FAQ the
> unofficial
> > BOINC Terms and Conditions document!
>
> I been called worse things ...
>
> I am afraid when I saw that one, I could not resist ... one of these days when
> my sense of humor is in REAL fine shape I am going to go in and add to it ...

I couldn't resist either. Just friendly teasing! :)

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