[COFF] [TUHS] Re: the wheel of reincarnation goes sideways

[Dan Cross]

On Thu, Mar 9, 2023 at 3:09 PM Larry McVoy <lm at mcvoy.com> wrote:
> On Thu, Mar 09, 2023 at 02:55:44PM -0500, Dan Cross wrote:
> > On Wed, Mar 8, 2023 at 8:22???PM John Cowan <cowan at ccil.org> wrote:
> > > On Wed, Mar 8, 2023 at 2:53???PM Dan Cross <crossd at gmail.com> wrote:
> > >> But the
> > >> 3090 was really more like a distributed system than the Athlon box
> > >> was, with all sorts of offload capabilities. For that matter, a
> > >> thousand users probably _could_ telnet into the Athlon system. With
> > >> telnet in line mode, it'd probably even be decently responsive.
> > >
> > > I find that difficult to believe.  It seems too high by an order of magnitude.
> >
> > I'm not going to claim it would be zippy, but I do think it would work
> > acceptably.
> >
> > Suppose that 1000 users telnet'ed into the x86 machine, but remained
> > essentially idle; what resources would that consume? We'd have 1000
> > open TCP connections, a thousand shell processes, a thousand
> > telnetd's, etc.
>
> The early Unix code really did not like stuff like this.  Lots of linear
> scans through what were assumed to be short lists.  I still remember an
> SGI Challenge being brought to it's knees by a bunch of racks of modems.
> The same machine could move a ton of data but not when it was being
> forced through a zillion sockets.

Oh for sure I wouldn't try it on a VAX or PDP-11. I'm a bit surprised
by the SGI thing, to be honest, but only a bit: as you say, I think
that was just before the big push to make Unix really scalable.

> Linux seems well past that problem but it's possible that back in the
> Athlon days it still sucked.  I pinged Linus, if he remembers when the
> kernel got taught to scale on sockets I'll report back.

Thanks, I'm curious what he says.

        - Dan C.