Microsoft working on new systems language

[Andrei Alexandrescu]

On 12/29/13 12:47 PM, "Ola Fosheim Grøstad" 
<ola.fosheim.grostad+dlang at gmail.com>" wrote:
> On Sunday, 29 December 2013 at 20:36:27 UTC, Walter Bright wrote:
>> I'll reiterate that the GC will NEVER EVER pause your program unless
>> you are actually calling the GC to allocate memory. A loop that does
>> not GC allocate WILL NEVER PAUSE.
>
> That's fine, except when you have real-time threads.
>
> So unless you use non-temporal load/save in your GC traversal (e.g. on
> x86 you have SSE instructions that bypass the cache), your GC might
> trash the cache for other cores that run real-time threads which are
> initiated as call-backs from the OS.
>
> These callbacks might happen 120+ times per seconds and your runtime
> cannot control those, they have the highest user-level priority.
>
> Granted, the latest CPUs have a fair amount of level 3 cache, and the
> most expensive ones might have a big level 4 cache, but I still think it
> is a concern. Level 1 and 2 caches are small: 64KB/128KB.

I think you and others are talking about different things. Walter was 
referring about never invoking GC collection, not the performance of the 
GC process once in progress.

Andrei