[computer-go] Re: Mogo scalability

[Don Dailey]

Hideki Kato wrote:
> David Fotland: <065201c8adff$2b4a8970$81df9c50$@com>:
>   
>> The scalability study showed that mogo gains almost 100 rating points per
>> doubling of performance.
>>
>> But on CGOS, there is mogo 1 CPU and mogo 4 CPU.  I would expect the 4 CPU
>> mogo to be 150 rating points or more higher than 1 CPU.  But it is actually
>> only 40 points higher.
>>     
>
> I'm also wondering this for months.
>
> One reason of this discount is that the MoGo bros running on cgos are 
> the _big versions.  By my obserbation (they are running on my pcs and 
> both are Q6600/3GHz with different mother boards), mogo_big_4core's 
> perallelism is around 300% (by top command), perhaps due to its 
> heavier uct part (just my guess).
>
>   
>> I guess this is because in the rating study mogo was mostly playing other
>> mogo versions.  A the faster mogo can see everything the weaker mogo sees,
>> and more.
>>     
>
> I'm not sure.  Mogo_big_4core's winning rate against mogo_big_1core is 
> about 60% (1641 / 2743) which corresponds only +70 ELO and current 
> rating difference on cgos is about 40, as you wrote.  According to the 
> scaling rule of mc playouts, it should be 160 ELO (log2(3) * 100 = 
> 158.5).
>
>   
>> But against other programs on CGOS, there will be weaknesses common to both
>> fast and slow mogo, that other programs might exploit.
>>
>> Is the true scalability of mogo (against a variety of programs, or against
>> people) less than the rating study indicates?
>>     
>
> I believe their current ratings on cgos indicate so.
>
>   
You should look on the All Time Ratings list to get a more correct 
picture.   I will try to update it today but we still have 551 games on 
the all time list for mogo-big-4 core:

It shows    mogo-big-4core as 2563  +35  -35
and         mogo-big-1core as 2480  +24  -24


Also,   don't forget that 4 cores are not as efficient as 1 core,   so 
we shouldn't expect this to be as good as the 1 core version running 4x 
longer.      I would expect it to be much better than 2x though - 
perhaps the mogo team can comment on that.

- Don



> Hideki
>
>   
>> David
>>
>>
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>>     
> --
> gg at nue.ci.i.u-tokyo.ac.jp (Kato)
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