10 Jan
2024
10 Jan
'24
10:22 a.m.
SPARCv9 has %tick register which just counts up on each clock cycle. Older
SPARCs don't have that. I'd still suspect you'd get non-unique results in
a
multi CPU machine without additional effort.
On Sat, Dec 2, 2023 at 10:02 PM ron minnich <rminnich(a)gmail.com> wrote:
SunRPC, among other protocols, needs transaction IDs
(XIDs) to distinguish
RPCs.For SunRPC, it's important that XIDs not be reused (not for all
protocols; 9p has no such requirement). Stateless protocols like NFS and
reused XIDs can get messy.
There is a vague, 30 year old memory, I have, that at some point SPARC got
a time register, or some other register, that always provided a different
answer each time it was read, even if read back to back, in part to enable
creation of non-reused XIDs. Note that things like the TSC or RISC-V MTIME
register make no such guarantee.
I am pretty sure someone here can fill me in, or tell me I'm wrong, about
my SPARC memory.
thanks