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Subject: Re: Pentium 4 and hyperthreading (to Charles Worthington)

Author: Charles Worthington

Date: 12:59:57 02/19/03

Go up one level in this thread


On February 19, 2003 at 15:38:02, martin fierz wrote:

>On February 19, 2003 at 14:57:18, Aaron Gordon wrote:
>
>>Hyatt has two CPUs. Each CPU will provide about a 16% boost in crafty from
>>Hyper-threading so 16% X 2 = 32%. Pretty much identical to his claim.
>
>i don't follow this math. one CPU = 100%, hyperthreading on =116%.
>by this account 2 CPUs are 200% and hyperthreading 2*116=232%. that is
>still only a 16% speedup...
>
>cheers
>  martin

>Actally martin it is 32% it is 16% per cpu times 2. The math is correct.
Charles
>


>>Now, I'd prefer if when he said this he did it in a bit more detail instead of
>>saying, "Oh, Hyperthreading gives you a 30-33% boost". IMO it should be worded,
>>"With two Xeon chips hyperthreading produces around a 30% speedup in Crafty.
>>This is around 15% per cpu".
>>
>>On February 19, 2003 at 14:17:55, Steffen Basting wrote:
>>
>>>Hi!
>>>I've posted some benchmark results on my PIV 3.06 earlier and your 1.33 factor
>>>in speed up seems to be a little too optimistic. Crafty benefits most from
>>>hyperthreading (about 20%), the usual nodes per second increase (Deep Shredder 6
>>>and Deep Fritz 7) is about 10% at maximum. Perhaps Xeons perform better, but I
>>>don't think the hyperthreading performance differs too much.
>>>
>>>----- Crafty, 1 Thread -----
>>>White(1): hash 96M
>>>hash table memory = 96M bytes.
>>>White(1): smpmt=0
>>>parallel threads disabled.
>>>White(1): bench
>>>Running benchmark. . .
>>>......
>>>Total nodes: 48447803
>>>Raw nodes per second: 1211195
>>>Total elapsed time: 40
>>>SMP time-to-ply measurement: 16.000000
>>>
>>>----- Crafty, 2 Threads -----
>>>White(1): hash 96M
>>>hash table memory = 96M bytes.
>>>White(1): smpmt=2
>>>max threads set to 2
>>>White(1): bench
>>>Running benchmark. . .
>>>......
>>>Total nodes: 48586305
>>>Raw nodes per second: 1429008
>>>Total elapsed time: 34
>>>SMP time-to-ply measurement: 18.823529
>>>
>>>----- Shredder 6-Mark, 1 Thread -----
>>>655+-44, 490kn/s
>>>
>>>----- Shredder 6-Mark, 2 Threads -----
>>>696+-45, 502kn/s
>>>
>>>----- Deep Fritz 7-Mark, 1 Thread -----
>>>1433+-0, 1193kn/s
>>>
>>>----- Deep Fritz 7-Mark, 2 Threads -----
>>>1602+-0, 1352kn/s
>>>
>>>Regards, Steffen.
>>>
>>>PS: The Crafty version I used was 18.6-smp from Bob's site, perhaps newer
>>>versions are optimized for hyperthreading?



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