Re: [ANNOUNCE] Interbench v0.20 - Interactivity benchmark

[Bill Davidsen <davidsen@tmr.com>]

Con Kolivas wrote:

>On Thu, 14 Jul 2005 03:54, Bill Davidsen wrote:
>  
>
>>Con Kolivas wrote:
>>    
>>
>>>On Tue, 12 Jul 2005 21:57, David Lang wrote:
>>>      
>>>
>>>>for audio and video this would seem to be a fairly simple scaleing factor
>>>>(or just doing a fixed amount of work rather then a fixed percentage of
>>>>the CPU worth of work), however for X it is probably much more
>>>>complicated (is the X load really linearly random in how much work it
>>>>does, or is it weighted towards small amounts with occasional large
>>>>amounts hitting? I would guess that at least beyond a certin point the
>>>>liklyhood of that much work being needed would be lower)
>>>>        
>>>>
>>>Actually I don't disagree. What I mean by hardware changes is more along
>>>the lines of changing the hard disk type in the same setup. That's what I
>>>mean by careful with the benchmarking. Taking the results from an athlon
>>>XP and comparing it to an altix is silly for example.
>>>      
>>>
>>I'm going to cautiously disagree. If the CPU needed was scaled so it
>>represented a fixed number of cycles (operations, work units) then the
>>effect of faster CPU would be shown. And the total power of all attached
>>CPUs should be taken into account, using HT or SMP does have an effect
>>of feel.
>>    
>>
>
>That is rather hard to do because each architecture's interpretation of fixed 
>number of cycles is different and this doesn't represent their speed in the 
>real world. The calculation when interbench is first run to see how many 
>"loops per ms" took quite a bit of effort to find just how many loops each 
>different cpu would do per ms and then find a way to make that not change 
>through compiler optimised code. The "loops per ms" parameter did not end up 
>being proportional to cpu Mhz except on the same cpu type.
>
>  
>
>>Disk tests should be at a fixed rate, not all you can do. That's NOT
>>realistic.
>>    
>>
>
>Not true; what you suggest is another thing to check entirely, and that would 
>be a valid benchmark too. What I'm interested in is what happens if you read 
>or write a DVD ISO image for example to your hard disk and what this does to 
>interactivity. This sort of reading or writing is not throttled in real life.
>

Of course it is. At least the read. It's limited to the speed needed to 
either play (watch) the image or to burn it.

-- 
bill davidsen <davidsen@tmr.com>
  CTO TMR Associates, Inc
  Doing interesting things with small computers since 1979