Help: socket buffer size

[Chris Torek]

> I am going to increase the size of socket buffers on 4.2BSD.
> Before doing it, I would like to ask advice of wizards in netlands:
>    i) what is the limit of the socket buffer size?
>   ii) if I increase the size, does it affect the kernel operation?

There isn't really *a* "socket buffer size".  There are a bunch of
places that have various "recvspace" and "sendspace" variables
(look for calls to soreserve()).  These can be increased (and in
fact many of them have been increased in 4.3) without affecting
much other than the number of mbufs in use.  I have heard somewhere
that increasing tcp_sendspace and tcp_recvspace above about 12K
causes a crash, but I haven't seen it happen (then again we haven't
been running "plain" 4.2 for a long time).  You might have problems
if they are >16K, since things like windows are kept in shorts and
signs of differences determine whether one number is "greater" or
"less" than another... but 4K is lots anyway.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 4251)
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