[PATCH] c++: implement C++17 hardware interference size

[Richard Earnshaw]

On 16/07/2021 12:17, Jonathan Wakely via Gcc-patches wrote:
> On Fri, 16 Jul 2021 at 03:51, Noah Goldstein wrote:
>> On intel x86 systems with a private L2 cache the spatial prefetcher
>> can cause destructive interference along 128 byte aligned boundaries.
>> https://www.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-optimization-manual.pdf#page=60
> 
> Which is a good example of why these "constants" should never have
> been standardized in the first place. Sigh.
> 

+1 for that.

I'll have a chat with our architecture guys, but I've no idea if they'll 
commit to any (useful) values for either constant.

R.