Wondering about tinyBenchmarks... (was Re: [squeak-dev] Cog 2776 on Intel i7-4790K @ 4GHz)

Göran Krampe goran at krampe.se
Mon Sep 1 21:29:35 UTC 2014


Hi Eliot!

On 09/01/2014 03:39 PM, Eliot Miranda wrote:
> Hi Göran,
>
> On Sep 1, 2014, at 6:06 AM, Göran Krampe <goran at krampe.se> wrote:
>> Hi guys!
>>
>> While on the subject of tinyBenchmarks (toying with comparing to
>> LuaJIT2), can someone explain a few things to me:
>>
>> - Why do we take "500000 / <the-time-to-run-benchmark>" to mean
>> bytecodes/sec? I presume its because someone made a count at some
>> point that it takes 500000 bytecodes to find those primes? Is that
>> still a correct estimation/presumption?
>
> That's right.  It's probably still close.  One can count the actual
> number by simulating the expression using (IIRC) run:atEachStep:
> which is in the class side of ContextPart.

Ah, good. So I am not entirely stupid. :)

>> - Why is benchFib not a correct Fibonacci sequence?
>
> BTW Fibonacci sequences have been generalized.  See Lucas Numbers on
> Wikipedia.  Ffor example the classic one is close to 2^N, but one
> which added the previous three results would be close to 3^N, etc
> ("tribonacci").
>
> But the point of benchFib is that it adds one for each and every
> invocation whereas the classic one adds one for each leaf activation.
> Hence benchFib's result is the number if activations required to
> evaluate it and hence dividing the result by the time in seconds
> taken to compute it gives a rough measure of activations per second.
> This really should be in the comment.

Ah, great! Thank you, I knew it must be something "smart" :)

regards, Göran


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