I notice that it would process 2 units at once. I know with Seti Driver, processing 2 at once would create more results, but the time it took to crunch each were longer than with just one at a time. I was wondering if this would react similar? I am only running one now, to see how much difference there is.

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<img src="http://www.setisynergy.com/images/stats/197876sah.png"></img>

Just noticed another problem. When I try to use Nero to read/burn something, BOINC stops, even though I have it selected to run all the time.

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<img src="http://www.setisynergy.com/images/stats/197876sah.png"></img>

Hawk,

HT = 2 Pretend CPUs on One real CPU (as you said).

When it is setup to pretend to be two, WUs run in parallel, but they share the same CPU Level 2 Cache, and RAM...and so are not quite twice as fast as one CPU.

To do the test you are discussing, I suggest you restart the machine, and go into the BIOS and turn off Hyperthreading for a true "one CPU" one thread test.

...or...you could do 3 tests.
1. HT on - 2 Threads (normal)
2. HT on - 1 Thread (ie use at most 1 CPU on preferences)
3. HT off - 1 Thread

I, for one, would be interested to know your results.

I have an HP machine, so I am thinking I can't turn HT off. I don't recall seeing it in the Bios but I can check later. I would still like advice on the problem with the crunching stopping while Nero is running. I normally leave my pc on 24/7 crunching, so I hate to see it stop for any reason.

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<img src="http://www.setisynergy.com/images/stats/197876sah.png"></img>

> Just noticed another problem. When I try to use Nero to read/burn something,
> BOINC stops, even though I have it selected to run all the time.
>
BOINC (science application) is set to run at the absolute lowest priority...and Nero is set to run at highest (when it sets up read from HDD and writes to CD/DVD burner) so BOINC might not get much CPU time.

I've found with just 4x DVD burning BOINC gets some of the CPU time...but I was using Easy CD creator 5.x.

Just noticed that even though I set BOINC and Nero priority at normal under task manager, NERO is still stealing 98-99% of the CPU. Argh.

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<img src="http://www.setisynergy.com/images/stats/197876sah.png"></img>

I do a lot of reading/burning, so this ain't good.

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<img src="http://www.setisynergy.com/images/stats/197876sah.png"></img>

Just noticed that even though I set BOINC and Nero priority at normal under task manager, NERO is still stealing 98-99% of the CPU. Argh.
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It's either that or NERO simply is not going to run & you will end up locking up your Computer ...

Nero always ran with the old Seti, but alas...

Anyway, I found a workaround and DVD Shrink seems to work with Boinc pretty well and it has a burner also. Well, it uses the Nero burning ROM, but it seems to work. Kewl.

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<img src="http://www.setisynergy.com/images/stats/197876sah.png"></img>

This may - or may not - help in regards to undrtstanding HT and SETI-classic.

I have 2 identical 3.0Gh P4's with 1Gb memory

Before BOINC, I ran one with HT on and the other with HT off ( for a short test).

I understand that the mix of WU's were not identical and don't count the same as in BOINC but it's the best test I have ...

WU's Total CPU time Avg CPU time
W/HT on 38 123h37m 3h15m11.6s
W/HT off 23 55h33m 2h24m57.2s

Just fyi ...

EdwardPF

> Hawk,
>
> HT = 2 Pretend CPUs on One real CPU (as you said).
>
> When it is setup to pretend to be two, WUs run in parallel, but they share the
> same CPU Level 2 Cache, and RAM...and so are not quite twice as fast as one
> CPU.
>
> To do the test you are discussing, I suggest you restart the machine, and go
> into the BIOS and turn off Hyperthreading for a true "one CPU" one thread
> test.
>
> ...or...you could do 3 tests.
> 1. HT on - 2 Threads (normal)
> 2. HT on - 1 Thread (ie use at most 1 CPU on preferences)
> 3. HT off - 1 Thread
>
> I, for one, would be interested to know your results.
>

Interesting. I would have thought HT on would be faster.

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<img src="http://www.setisynergy.com/images/stats/197876sah.png"></img>

Well I'm not seeing an option in the Bios to turn off HT. Are there any programs that might do it? I'm thinking no, but I would like to test it.

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<img src="http://www.setisynergy.com/images/stats/197876sah.png"></img>

> Interesting. I would have thought HT on would be faster.
>
HT is faster, actually.
Since boinc runs on 2 virtual CPUs, doing 2 WUs in parallel, you have to divide the CPU time by 2 to get the real performance.

Regards Hans

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WITH MY 3.40G HT i COMPLETE TWO WU IN ABOUT 3HR 30MIN TO 3HR 45MIN
WITH MY 2.53 G NO HT i COMPLETE ONE WU IN ABOUT 3HR 12MIN TO 3HR 45MIN

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Fred
BOINC Alpha, BOINC Beta, LHC Alpha, Einstein Alpha

> Since boinc runs on 2 virtual CPUs, doing 2 WUs in parallel, you have to
> divide the CPU time by 2 to get the real performance.

That is wrong. You crunch 2 WUS at the same time with HT, not one behind
the other. Thus each WU needs 3h15.

Example: Two Sprinters arrive after 10 seconds at the same time at the goal,
That means that each Sprinter needed 10 seconds for the distance and not 5sec.

> > Since boinc runs on 2 virtual CPUs, doing 2 WUs in parallel, you have to
> > divide the CPU time by 2 to get the real performance.
>
> That is wrong. You crunch 2 WUS at the same time with HT, not one behind
> the other. Thus each WU needs 3h15.
>
> Example: Two Sprinters arrive after 10 seconds at the same time at the goal,
> That means that each Sprinter needed 10 seconds for the distance and not 5sec.
>

If it takes Boinc 3 hours to crunch 2 wus at 3 hours each, that is the equivalent of 1 hour and 30 minutes each as you have produced 2wus in 3 hours.

I have a machine with 2 actual, and 2 virtual processors. Each wu takes about 3 hours. Therefore the 'real' time per wu is 45 minutes each. Or 32 wus per day.

Dunc

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LOL

If memory serves, the difference between a hyper-threading and non-hyper-threading computer lies in the processor's firmware, which is on the CPU - So I have to agree.

Hyper-threading aside, a uni-processing computer has only one physical processor, and that's what ought to count. So if you have one workunit completed in three hours by one processor pretending to be two, it's still three hours for the one physical processor.

Just my two cents.

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I love these discussions that confuse processing time with throughput ...

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My apologies, then. Hyper-threading being considered a doubling of processing as opposed to a processing method is what is causing my confusion.

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