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Subject: Re: Intel claims hyperthreading produces 900%+ boost (kinda OT)

Author: Robert Hyatt

Date: 20:44:17 12/06/02

Go up one level in this thread


On December 06, 2002 at 19:33:58, Vincent Diepeveen wrote:

>On December 06, 2002 at 11:53:26, Robert Hyatt wrote:
>
>>On December 06, 2002 at 10:31:54, Vincent Diepeveen wrote:
>>
>>>On December 06, 2002 at 10:24:22, Robert Hyatt wrote:
>>>
>>>>On December 06, 2002 at 07:14:29, Vincent Diepeveen wrote:
>>>>
>>>>>On December 06, 2002 at 05:40:25, Matt Taylor wrote:
>>>>>
>>>>>>On December 06, 2002 at 05:09:03, Daniel Clausen wrote:
>>>>>>
>>>>>>>http://www.theinquirer.net/?article=6586
>>>>>>>
>>>>>>>I love marketing. :)
>>>>>>>
>>>>>>>Sargon
>>>>>>
>>>>>>Offhand I would have said the one on the left was a Williamette. ;)
>>>>>>Then again, Intel claimed that both chips had HT.
>>>>>>
>>>>>>The only thing I can figure is that someone made a big typo.
>>>>>>
>>>>>>-Matt
>>>>>
>>>>>Test results provided by Robert Hyatt i see in small font right bottom :)
>>>>
>>>>
>>>>What are you talking about here?  I haven't given them any results at all.  In
>>>>fact,
>>>>I have had a hyperthreading CPU in my office for two days now and the only
>>>>result I have provided to anyone was what I provided here (SMT on = 1.33X SMT
>>>>off).
>>>
>>>Can you please post verbose outputs with for each ply also the number
>>>of nodes printed?
>>>
>>>That factor 9 times speedup of their own test is a bit much though :)
>>>
>>>Thanks,
>>>Vincent
>>
>>
>>I can post output.  I can't print nodes between plies for the same reason I have
>>never
>>been able to do that.  All I can do is search to a specific depth and print the
>
>Why can everyone print nodes and you cannot?

Is it absolutely necessary that I explain this 6-8 times per year to you?
The reason hasn't changed.  It won't change...


>
>Simple parallel insight.
>
>When you have a parallel program like crafty and end an iteration.


You have been asking me to print the nodes each time I print a new PV.
I can't do that because I split at the root.




>
>It is easy to proof then that no other thread is busy searching
>then, because otherwise you would not have finished the ply.
>
>Proof ends.


So?  I don't do this.  I am not going to do this.  end of story...
It serves _no_ purpose.




>
>Same is true for displaying mainlines when you don't split in root.

However I _do_ split in the root...


>
>In case of DIEP i nowadays simply have node counts for each processor.
>It simply adds up node counts of other processors at each mainline.
>
>It could be incorrect but practically that hardly happens. At end of
>iteration it is never incorrect though, despite that i do not lock.
>
>Best regards,
>Vincent
>
>>node counter
>>when the search completely stops.
>>
>>I ran a dual-thread test with SMT off, and a quad-thread test with SMT on.
>>
>>The single position I tried searched 1.5M nodes per second with SMT off, and
>>2.1M
>>nodes per second with SMT on.  I haven't had time to run exhaustive tests and I
>>haven't
>>tried to find time as I need to fix the spinlock and spinwait stuff anyway,
>>adding the
>>pause instruction...
>>
>>the 9x has to be a typo.  The best I have heard was Eugene's 2.0 speedup running
>>two
>>tablebase compression programs at the same time...



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