3 Dec
2023
3 Dec
'23
12:01 p.m.
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