D GC theory

[via Digitalmars-d]

On Tuesday, 24 February 2015 at 15:14:03 UTC, Ola Fosheim Grøstad 
wrote:
> On Tuesday, 24 February 2015 at 14:45:17 UTC, Marc Schütz wrote:
>> It's possible to (ab)use the MMU as a write barrier.
>
> Uhm...
>
> The throughput for L/SFENCE is 5 cycles and SFENCE 33 cycles... 
> The cost of a page miss is 1000 cycles + overhead for copying.
>
> And that's assuming that you have enough memory and that the 
> TLB isn't affected...

Yes, but if the program has a small working set, you pay that 
price only a few times (once per page), and in any case, only 
during a running background scan, rather than always.