The cost of write barriers

[Araq via Digitalmars-d]

On Sunday, 2 November 2014 at 08:48:46 UTC, Jonathan Barnard 
wrote:
> The upcoming version 1.4 of Go uses write barriers in 
> preparation for the future implementation of a concurrent and 
> generational GC. On the mailing list thread discussing the beta 
> (https://groups.google.com/forum/#!topic/golang-nuts/7VAcfULjiB8), 
> a few people note speed reductions of 30-50% in their 
> benchmarks. I think this vindicates to a degree D's decision to 
> avoid garbage collection strategies that require write barriers.

And I think these are meaningless results. You can see here for 
instance what a write barrier can look like:

http://psy-lob-saw.blogspot.de/2014/10/the-jvm-write-barrier-card-marking.html