[ale] Hyperthreading

[Dow Hurst]

Thinking over what I wrote and what I've experienced I can see how I need to 
clarify!

1. I don't know if the modelling apps calculation engine takes advantage of 
the hyperthreading in any way at all.

2.  The runs times are doubled when two jobs are running.  So one job is done 
in 25 minutes while two simultaneously running jobs are done in 45-50 minutes.

3.  The responsiveness of the machine while a single job was running may be 
the major benefit.  However, at home, my Athlon XP 1800 gives the same feel 
while a job is running.

 From those points, maybe HT isn't helping me at all.
Dow


Matt Smith wrote:
> Perhaps I'm missing something - unless your task utilizes multiple "processors" on a single run, you're getting no benefit of running two simultaneously.
> 
> You could expect the same on a non-hyperthreading CPU while running two instances.  Perhaps not as far as the responsiveness of the machine while one is running...  hopefully you can clarify.
> 
> 
> --Matt
> 
> 
> -----Original Message-----
> From: Dow Hurst [mailto:dhurst at kennesaw.edu]
> Sent: Wednesday, April 14, 2004 10:41 AM
> To: Atlanta Linux Enthusiasts
> Subject: Re: [ale] Hyperthreading
> 
> 
> Yes, I run two minimizations simultaneously on my single P4 and until the 
> second one starts the machine is very responsive.  It is truly like having a 
> dual CPU from my user perspective.  Run times are doubled on the minimizations.
> 
> 25m37.821s   Single run
> 
> 49m54.143s
> 44m10.795s   Dual runs (The second is the shorter due to different start 
> times, so this is general datapoints)
> 
> 
> These are GPCR receptor minimizations with delta 9 THC bound inside the 
> receptor.  About ~2700 atoms in vacuum using molecular mechanics and a lot of 
> torsional restraints applied.  Not a difficult calculation but is pure FPU on 
> C and Fortran code.  But, my point is the machine was acting like a dual CPU 
> machine in a very efficient manner.
> Dow
> 
> 
> Christopher Fowler wrote:
> 
>>How is the performance? Is there a real gain?
>>
>>On Wed, 2004-04-14 at 10:03, Jonathan Glass wrote:
>>
>>
>>>On Wed, 2004-04-14 at 10:02, Mike Millson wrote:
>>>
>>>
>>>>I have a box with a P4 processor running Slackware 9.1. What do I need
>>>>to do to enable hyperthreading support? Do I just have to compile a
>>>>kernel with SMP support? Are there any other kernel options or config
>>>>changes I need to make? Does anyone know of any good articles or howtos
>>>>on configuring linux for hyperthreading?
>>>>
>>>>Thank you,
>>>>Mike
>>>>
>>>>_______________________________________________
>>>>Ale mailing list
>>>>Ale at ale.org
>>>>http://www.ale.org/mailman/listinfo/ale
>>>
>>>You win the prize on the first toss.  Just recompile with SMP support,
>>>and enable HT in your BIOS, and voila!  Instant SMP machine.
>>
>>
>>_______________________________________________
>>Ale mailing list
>>Ale at ale.org
>>http://www.ale.org/mailman/listinfo/ale
>>
> 
> 

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Dow Hurst                  Office: 770-499-3428            *
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