On 20/02/2020, arnold(a)skeeve.com <arnold(a)skeeve.com> wrote (in part):
Also, early Solaris was a dog. Performance was poor.
It improved over
time, but it wasn't until around Solaris 2.4 or 2.5 that running it wasn't
painful.
I recall that Sun salesfolk came in to sell us something-or-other and
freely admitted that Slowlaris did not improve until dtrace came
along, at which point Sun dived into system calls.
N.