Slower than Python

[John Colvin]

On Saturday, 2 March 2013 at 20:02:09 UTC, Walter Bright wrote:
> On 3/2/2013 11:42 AM, Russel Winder wrote:
>> On Sat, 2013-03-02 at 11:30 -0800, Walter Bright wrote:
>>> On 3/2/2013 7:43 AM, Russel Winder wrote:
>>>> For writing interpreters, RPython spanks C.
>>>
>>> What's RPython doing that makes it faster?
>>
>> Allowing PyPy to have a good JIT compiler.
>
> I don't understand. Does that JIT generate faster code than a C 
> compiler would generate?

In some cases yes, it can,  but as you know that has nothing to 
do with the language the jit is written in. As I've said 
elsewhere, pypy being fast compared to cpython has nothing to do 
with the former being written in rpython and the latter in c*

*other than perhaps the higher productivity of writing in rpython 
allowing more resources to be dedicated to optimisation.