[Python-Dev] Bytecode analysis

[Christian Tismer]

Neil Schemenauer wrote:
> Christian Tismer wrote:
> 
>>Where you really can save some time is to shortcut some
>>of the very short opcodes to not jump back to the ticker
>>counting code, but into a shorter circle.
> 
> 
> 2.2 -> 2.3 includes this optimization for some opcodes.

Oh! *blush*
I should read more of this :-)

>>Not trying to demoralize you completely, but there are
>>limits about what can be gathered by optimizing the
>>interpreter loop. There was once the p2c project, which
>>gave an overall improvement of 25-40 percent, by totally
>>removing the interpreter loop.
> 
> 
> Yes, but p2c was probably not nice to the icache.  I doubt 25-40% is
> an upper bound.  Memory bandwidth really sucks now (relatively
> speaking).  I think reference counting is now starting to look like a
> smart design (in terms of performance). :-)

Yes, it created lots of code, and for sure, code repetition
can be helpful, if the relevant pieces are kept tightly together.
But I still doubt bigger improvements, since most of the time
is spent in the C library code. You need to optimize this
away, too.

ciao - chris

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