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Subject: Re: tip for "simulating" an MP computer & performance of ABDADA

Author: Tom Kerrigan

Date: 20:25:40 05/28/00

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On May 28, 2000 at 22:23:48, Peter Kappler wrote:

>On May 28, 2000 at 20:43:18, Tom Kerrigan wrote:
>
>>I found out that running multiple threads on one processor is not necessarily a
>>good way to simulate an MP computer. You have to make sure each thread only
>>searches one node per timeslice. If you're running Windows, you can do this by
>>calling Sleep(0) once per node.
>>
>>I implemented Jean-Christophe Weill's ABDADA parallel search algorithm and I'm
>>very happy with it. In terms of node counts, I get the following speedups when
>>running BK:
>>
>>Threads     Speedup
>>1           1
>>2           1.81
>>4           3.32
>>8           5.66
>>
>>My implementation is pretty crude, so hopefully these numbers will improve over
>>time. I'm not sure how this algorithm compares to others, but I like it for a
>>few reasons:
>>1) it's very easy to understand and implement
>>2) it doesn't require any communication between threads, except for a fancy
>>shared hash table
>>3) if some threads barf, the search can still finish (this hasn't happened to me
>>yet, but it's cool for peace of mind)
>>
>>-Tom
>
>
>
>Looks interesting.  Where can I find more info?
>
>--Peter

The paper was published in an ICCA journal a few years ago. I found it recently
on the web. I can't remember which search engine I used to find it, or exactly
what I searched for, but it wasn't so hard.

-Tom



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