11 Jun
2025
11 Jun
'25
2:53 p.m.
On Wed, Jun 11, 2025 at 10:22 AM Warner Losh <imp(a)bsdimp.com> wrote:
On Wed, Jun 11, 2025 at 9:56 AM Dan Cross
<crossd(a)gmail.com> wrote:
I could definitely imagine someone saying something like, "well, it's
not _true_ multiprocessor support" since it really does appear that
the kernel was restricted to running on one CPU at a time.
However, it seems like the LWP support in those versions allows a
single process to run across multiple CPUs, so there's that.
- Dan C.
[snip]
I don't know when exactly it came around. It was definitely in 4.1.4,
and I'm also certain it was in 4.1.3/4.1.3_U1.
If Wikipedia can be trusted, it says that MP support came in 4.1.2,
for the SPARCserver 600MP systems. It looks like it only supported up
to 4 CPUs.
There's #ifdef MUlTIPROCESSOR in the 4.1.3 and 4.1.4 trees that
leaked. But it looks like they only work for sun4m machines have real
defines...
I'd been told at the time, over lunch, that even those code bases
didn't have MP support, but it may have been SMP support was
lacking...