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Subject: Re: Some thoughts for those who are considering to buy a Dual processor PC

Author: Andrew Dados

Date: 05:52:15 03/27/01

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On March 27, 2001 at 08:17:43, Vincent Diepeveen wrote:

>On March 26, 2001 at 22:44:53, Robert Hyatt wrote:
>
>>On March 26, 2001 at 20:54:48, Dan Andersson wrote:
>>
>>>I have to agree that multibanked memory and lage cashe size are very beneficial.
>>>Those factors could very well explain the superlinearity.
>>>
>>>Regards Dan Andersson
>>
>>
>>I don't think the 4-way interleaving helps.  That _barely_ lets the machine
>>hold its own, memory-wise, because there are 4x as many cpus fighting over
>>access to memory... making it nearly 4x faster just barely breaks even.  The
>>larger L2 cache may well make a difference, of course...
>
>You speak for Crafty. I speak for DIEP.
>I'm doing 8 probes of at least 16 bytes an entry.
>that's 128 bytes.

My guess is big difference for SMP DIEP is running separate processes instead of
threads. 8 probes is just icing on that cake.

For what I know windows (unix too) will load each process to its own address
space, so they will fight for L3 cashe.
Or am I totally wrong here?

-Andrew-


>
>I also do that to get a possible evaluation out of hashtable as i store
>evaluations in hashtable.
>
>So i do way more of those octo-probes as most progs try the hashtable...
>
>Further my whole program is made out of 'int'. So that means in short
>that all kind of tables are 4 times bigger (in bytes) as they could
>be. That means that when compared to some years ago i need quite some
>accesses to main memory.
>
>Both the bigger L2 cache and the faster memory helps a lot then.
>
>Best Regards,
>Vincent



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