Re: Platform specification questions
On Mon, Dec 13, 2021 at 02:00:38PM -0800, Greg Favor wrote:
On Mon, Dec 13, 2021 at 11:06 AM Vedvyas Shanbhogue <ved@...>Totally agree that the term "cache structure" is ambigous and variety of caches may be built. How caches are built should also be transparent to the ISA, software, and the platform in general. Like you said reliability engineering is not something that affects software compatibility or hardware/software contracts. And as you rightly pointed out, caches are most obvious but a reliable system will need more such as right thermal engineering, stable clock/voltage delivery, right ageing guardbands, use of gray codes when appropriate, voltage monitors, timing margin sensors, protection on data/control buses, protection on register files, protection on internal data paths, etc.
I would be totally okay with saying drop this whole paragraph.
Mandate: *At a minimum, caching structures must be protected such thatWould a mandate be overeaching and why limit it to caches then?
A product may define its reliability goals and may reason that a certain cache need not be protected due to various reasons like the technology in which the product is built, the altitude at which it is supposed to be used, the architectural vulnerability factor computed for that structure, etc.
I am failing to understand how would we be adding to or removing from the OS-A platform compatibility goals which is to be able to boot a shrink wrapper server operating system by trying to provide a mandate on how it implements reliability?