[fpc-devel] Modernising Pascal

[Jamie McCracken]

Jonas Maebe wrote:
> 
> On 24 feb 2005, at 13:51, Jamie McCracken wrote:
> 
>>> IMO the best solution for (almost) all of your problems were garbage
>>> collection. GC is part of Oberon, and it would fit into .NET/DotGNU as
>>> well.
>>
>>
>> GC is very inefficient with memory and current implementations tend to 
>> cost a lot performance wise too.
> 
> 
> It's *much* faster than reference counting everything. Reference 
> counting is more or less the slowest garbage collection technique there 
> is (except if only very few objects have to garbage collected). It also 
> can't deal with circular references.

Thats why I would want ref count for Tobjects and not Tcomponents. 
Partial ref counting should be faster than doing GC on everything.

> 
>> GC gets a lot slower with the more objects you create.
> 
> 
> Reference counting too.

GC is worse here because the pointers are not static in GC so 
referencing an object means looking up the actual address in a lookup 
list (so more overhead whenever you call a method or pass an object 
reference). GC does not use the stack efficiently and has to use a lot 
of heap so its extremely inefficient. Ever see GC compact swap?

> 
>> Mixing unmanaged with managed code cause severe performance issues 
>> (marshalling penalties calling ummanaged c functions)
>>
>> Interoperability with C gets increasingly difficult. Writing bindings 
>> becomes much more complicated and time consuming.
> 
> 
> You get the same problem if you pass a reference counted structure to C 
> (or any other language).

yes but with GC everything would have to be managed whilst just ref 
counting Tobject would not cause these problems (you cant access a 
tobject from C anyhow). Tobject is the only weak point in Delphi's 
memory management so I would say using GC to correct that would be overkill.

jamie.

> 
> 
> Jonas
> 
> 
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