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* [TUHS] scaling on TCP socket connections
@ 2023-03-10  0:23 ron minnich
  2023-03-10  0:42 ` [TUHS] " David Arnold
                   ` (2 more replies)
  0 siblings, 3 replies; 9+ messages in thread
From: ron minnich @ 2023-03-10  0:23 UTC (permalink / raw)
  To: The Eunuchs Hysterical Society

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Ca. 1981, if memory serves, having even small numbers of TCP connections
was not common.

I was told at some point that Sun used UDP for NFS for that reason. It was
a reasonably big deal when we started to move to TCP for NFS ca 1990 (my
memory of the date -- I know I did it on my own for SunOS as an experiment
when I worked at the SRC -- it seemed to come into general use about that
time).

What kind of numbers for TCP connections would be reasonable in 1980, 90,
2000, 2010?

I sort of think I know, but I sort of think I'm probably wrong.

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* [TUHS] Re: scaling on TCP socket connections
@ 2023-03-10 10:14 Paul Ruizendaal via TUHS
  0 siblings, 0 replies; 9+ messages in thread
From: Paul Ruizendaal via TUHS @ 2023-03-10 10:14 UTC (permalink / raw)
  To: tuhs


From reading a lot of papers on the origins of TCP I can confirm that people appear to have been thinking in terms of a dozen connections per machine, maybe half that on 16-bit hardware, around 1980. Maybe their expectations for PDP-10’s were higher, I have not looked into that much.

> From: Tom Lyon <pugs78@gmail.com>

> Sun chose UDP for NFS at a point when few if any people believed TCP could
> go fast.
> I remember (early  80s) being told that one couldn't use TCP/IP in LANs
> because they were WAN protocols.  In the late 80s, WAN people were saying
> you couldn't use TCP/IP because they were LAN protocols.

I’m not disputing the above, but there was a lot of focus on making TCP go fast enough for LAN usage in 1981-1984. For example see this 1981 post by Fabry/Joy in the TCP-IP mailing list: https://www.rfc-editor.org/in-notes/museum/tcp-ip-digest/tcp-ip-digest.v1n6.1
There are a few other similar messages to the list from around that time.

An early issue was check-summing, with that initially taking 25% of CPU on a VAX750 when TCP was heavily used. Also ideas like having "trailing headers" (so that the data was block aligned) were driven by a search for LAN performance. Timeouts were reduced from 5s and 2s to 0.5s and 0.2s. Using a software interrupt instead of a kernel thread was another thing that made the stack more performant. It always seemed to me that the BBN-CSRG controversy over TCP code spurred both teams ahead with BBN more focussed on WAN use cases and CSRG more on LAN use cases. I would argue that no other contemporary network stack had this dual optimisation, with the possible exception of Datakit.



^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2023-03-10 15:10 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-03-10  0:23 [TUHS] scaling on TCP socket connections ron minnich
2023-03-10  0:42 ` [TUHS] " David Arnold
2023-03-10  0:48 ` Warner Losh
2023-03-10  0:59 ` Tom Lyon
2023-03-10  1:24   ` Lawrence Stewart
2023-03-10  1:32   ` Larry McVoy
2023-03-10 10:14     ` Ralph Corderoy
2023-03-10 15:10       ` Larry McVoy
2023-03-10 10:14 Paul Ruizendaal via TUHS

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