In Solaris, how we can find the status or check hyper-threading or multi-threading is enabled or not using commands?
psrinfo command, to view info of your CPUs:
psrinfo -vp to view info of physical and virtual CPUs,
psrinfo to view online/offline CPUs.
Let's say you have 4 CPUs, including HT virtual CPUs, 0-3, and want to disable HTs. They will be presented in pairs, 1st physical will have (0,2), 2nd (1,3). 2 and 3 are the HTs.
psradm -f 2 3 will disable them (offline).
psrinfo to view the online/offline CPUs (check the difference)
psradm -n 2 3 to enable them (online).
These settings are runtime only. You must enable/disable HT through BIOS/EFI for persistence. I've tested these on Solaris 11.4 x86.