A few thoughts on std.allocator

Panke via Digitalmars-d digitalmars-d at puremagic.com
Sun May 10 04:05:47 PDT 2015

On Sunday, 10 May 2015 at 10:51:54 UTC, Michel Fortin wrote:
> On 2015-05-10 09:50:00 +0000, Andrei Alexandrescu 
> <SeeWebsiteForEmail at erdani.org> said:
>> 3. Thread-local vs. shared objects
>> Currently in D it's legal to allocate memory in one thread and 
>> deallocate it in another. (One simple way to look at it is 
>> casting to shared.) This has a large performance cost that 
>> only benefits very few actual cases.
>> It follows that we need to change the notion that you first 
>> allocate memory and then brand it as shared. The "will be 
>> shared" knowledge must be present during allocation, and use 
>> different methods of allocation for the two cases.
> Shared is implicit in the case of immutable. Think carefully: 
> if you implement this and it has any efficiency benefit for 
> non-shared allocations, const-allocated objects and arrays will 
> become more performant than immutable-allocated ones. People 
> will thus have an incentive to stay away from immutable.

If immutable does not pull its weight in other ways, it's just 
not worth it.

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