garbage collection in d

[Robert Jacques]

On Wed, 07 Apr 2010 17:34:09 -0300, Jacob Carlborg <doob at me.com> wrote:

> On 4/7/10 20:40, Sean Kelly wrote:
>> Daniel Oberhoff Wrote:
>>>
>>> b) my reluctance to the dependency on a complex runtime as the one d i
>>> is bringing at least due to its garbage collector
>>>
>>> b) worries me a little. I am working towards real time systems with
>>> tight time and sometimes also tight memory constraints, and a
>>> conservative stop-the-world collector seems a bit daunting in this
>>> context. is it reasonable to work without the collector, or are there
>>> plans to upgrade to a concurrent one. also are there extensive
>>> performance tests as how badly the collector interrupts real-time
>>> processing?
>>
>> It's still possible to build druntime with a custom GC.  You can even  
>> have a "GC" that simply calls malloc/free if you avoid coding that  
>> relies on implicit collection of discarded memory.  See gc_stub for an  
>> example.  As for better GC implementations, there are a bunch of  
>> options, but I don't know that we can go so far as an incremental  
>> collector ala Java.  That D can call C code causes problems there.
>
> Maybe something like the AutoZone collector on Mac OS X:  
> http://www.opensource.apple.com/source/autozone/autozone-77.1/README.html?f=text
>
> "AutoZone is a scanning, conservative, generational, multi-threaded  
> garbage collector."
>
> "... the implementation is language agnostic".
>
> "The AutoZone collector is implemented in C++ and is designed to work in  
> a runtime where some or most of the application's memory may be managed  
> by mechanisms other than the collector."

Via reddit:
> How does it compare to boehm?
>> Boehm is a drop in replacement for malloc. Autozone requires changes to  
>> the compiler to emit write barriers, and enforces certain coding  
>> constructs - so it doesn't "just work" and requires some changes to  
>> adopt it. But autozone can be more efficient at collecting as a result.
>> Also autozone collects and runs finalizers in a background thread -  
>> AFAIK Boehm does not.It's better for interactive desktop apps. Boehm is  
>> better for long-running server processes. The trade off is more  
>> fragmentation with AutoZone for faster speeds for relatively  
>> short-living desktop apps.

So autozone is language agnostic but not compiler agnostic, so calling C  
functions or using assembly is still a problem.