[Pythonmac-SIG] Pystone numbers for different Macs...

[Jack Jansen]

On 20-Jan-2008, at 19:23 , Daniel Lord wrote:

> I ran the test  on my 1st Gen Quad Core ( 2 x Quad-core 3.0 GHz, 13GB
> RAM) and was a bit surprised to see  little improvement over the Core
> Duo numbers.
>
> 63019.7 pystones/second
>
> I am assuming the GIL is limiting  threading and therefore I am really
> running on one or two cores--hence the tangible improvement is just
> CPU speed: from 2.33 GHz to 3.0 GHz and a bit of the memory bandwidth
> increase as well.


Interesting...
My first generation quadcore at 2.6 Ghz clocks at 62578.2.

So there's another limiting factor: from my machine to yours is a 15%  
speed bump, but only a 1% increase in pystone numbers.

Somebody told me recently that MacOSX is not very good for fast task  
switching with multiprocessors, because apparently (his words, and  
possibly misrepresented by me) the implementation of semaphores sucks.  
This seems to corroborate that.

Hmm, what is your bus speed? Mine is 1.33 Ghz, is yours that as well  
is it 1.5 Ghz? If the former it could be that semaphores somehow run  
at bus speed and semaphore overhead dwarves any processing done. If  
your bus runs at 1.5Ghz there must be yet another bottleneck...
--
Jack Jansen, <Jack.Jansen at cwi.nl>, http://www.cwi.nl/~jack
If I can't dance I don't want to be part of your revolution -- Emma  
Goldman