[pypy-dev] PyPy 1.1 beta release

[Janzert]

Carl Friedrich Bolz wrote:
> Niko Matsakis wrote:
>> On Apr 20, 2009, at 8:36 PM, Jacob Hallén wrote:
>>
>>> I think this formulation is a bit confusing. It is not our speed 
>>> that is 0.8-2x CPython, it is our performance relative to CPython
>>> that is between 0.8 and 2, with 0.8 meaning that we are faster than
>>> CPython on those benchmarks, and 2 meaning that we need twice the
>>> time to run the benchmark.
>> Maybe I am a bit confused, but I don't see a difference between those
>>  two things?
>>
>> i.e., if the speed is 0.8x CPython, to me that means that it runs in
>>  80% of CPython's time (i.e., faster), whereas 2x CPython would be 
>> twice as much time.
>>
>> In any case, I agree that the second formulation is phrased more 
>> clearly, just curious if my understanding of 0.8x is flawed.
>>
> 
> Hi Niko,
> 
> FWIW, that's the reasoning we had when we wrote the thing. However, we 
> keep having this discussion every time we write something about 
> performance, so I guess it's not as clear as you and me think :-).
> 
> Carl Friedrich

I've seen this discussion several times and not only in pypy related
contexts. It seems that the majority of native English speakers (or
possibly it's just American's?) interpret the statement in exactly the
opposite way the majority of non-native speakers do. With "2x of the
speed" being interpreted as two times faster by native speakers and as
taking twice the amount of time by non-native speakers.

Janzert