[squeak-dev] laboratoryGains ~= realWorld gains (was: The Trunk: ShoutCore-eem.62.mcz)

Eliot Miranda eliot.miranda at gmail.com
Sat Dec 1 18:03:30 UTC 2018


Hi Chris,

    I think you have a point.  Are you going to propose a change?

_,,,^..^,,,_ (phone)

> On Nov 30, 2018, at 2:34 PM, Chris Muller <asqueaker at gmail.com> wrote:
> 
> Unrelated to the change itself, here's another example of the
> deleterious effects of trying to improve performance at the expense of
> proper encapsulation and late-binding dynamism.
> 
> I'm referring to the use of an IdentityDictionary for the Smalltalk
> Environment instead of a regular Dictionary.
> 
> Not ONLY does force ALL clients to make assumptions about internal
> implementation,
>  - not ONLY duplicating this poor #asSymbol coding style again and again,
>  - it actually screws them over on performance in the real world
>   -- where the class names are likely to have come from an external source,
>   therefore as a String, forcing an extra lookup in the Symbol table
> that is worse than the original single Dictionary lookup.
> 
> See?
> _______
> | iddict dict |
> iddict := Smalltalk globals instVarNamed: 'declarations'.
> dict := iddict as: Dictionary.
> {
> [ iddict at: 'Integer' asSymbol ] bench.
> [ dict at: 'Integer' ] bench
> }
> 
> #('1,490,000 per second. 669 nanoseconds per run.' '3,620,000 per
> second. 276 nanoseconds per run.')
> _______
> 
> Optimization is like whack-a-mole.  Optimizing one thing invariably
> incurs a cost on something else.  So would it not be best to choose
> the trade-offs that actually *gain in the real-world* than ones that
> gain only in the lab?  Chasing that last 1% gain achieved in the lab,
> narrowed the usability, resulting in across-the-board losses for the
> real world:  in code-quality, dynamism AND performance by a whopping
> 50%.
> 
> Regards,
>  Chris
> 
> 
>> On Thu, Nov 29, 2018 at 4:00 PM <commits at source.squeak.org> wrote:
>> 
>> Eliot Miranda uploaded a new version of ShoutCore to project The Trunk:
>> http://source.squeak.org/trunk/ShoutCore-eem.62.mcz
>> 
>> ==================== Summary ====================
>> 
>> Name: ShoutCore-eem.62
>> Author: eem
>> Time: 29 November 2018, 2:00:34.775887 pm
>> UUID: 45629ac9-52a5-412c-9bf1-493a0ac2ea36
>> Ancestors: ShoutCore-tpr.61
>> 
>> Fix a bug in SHMCClassDefinition>>sharedPools that answered nil as the pool for a missing pool, and hence broke khighlighting in the Monticello package browser when browsing older version s with different pool dictionary definitions.
>> 
>> =============== Diff against ShoutCore-tpr.61 ===============
>> 
>> Item was changed:
>>  ----- Method: SHMCClassDefinition>>sharedPools (in category 'act like a class') -----
>>  sharedPools
>>        | d |
>>        d := Set new.
>> +       classDefinition poolDictionaries do:
>> +               [:poolName|
>> +               (Smalltalk at: poolName asSymbol ifAbsent:[nil]) ifNotNil: [:pool| d add: pool]].
>> -       classDefinition poolDictionaries do:[:each |
>> -               d add: (Smalltalk at: each asSymbol ifAbsent:[nil]) ].
>>        ^d!
>> 
>> 
> 


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