Re: X much slower in 2.0.24 than in 1.2.13

Linus Torvalds (torvalds@cs.helsinki.fi)
Wed, 6 Nov 1996 11:47:33 +0200 (EET)

On Sun, 3 Nov 1996, Nuno Grilo wrote:
>
> In message <Pine.LNX.3.91.961103140922.4821A-100000@linux.cs.Helsinki.FI>, Linu
> s Torvalds writes:
> >
> >
> >Could people who run 2.0.24 and see the bothersome X slowdown just try to
> >reverse the patch to linux/net/core/sock.c?
>
> It didn't do any good.
> But reversing the changes to linux/include/net/sock.h and
> linux/net/ipv4/tcp_input.c solved the slowdown

Ok. The tcp_input.c patch should be totally innocent, as people have
verified that X over TCP is as fast in 24 as it was in 23 (easy to do:
do a

export DISPLAY=localhost:0

rather than just the normal ":0" to make the program use TCP rather than UNIX
domain sockets)

However, the net/sock.h change does two separate things:
- the TCP sequence number addition for ka9q-based stacks
- a 16->32 bit counter change

Can you test if the detrimental effect comes from _only_ the short->int
changes? In that case it seems like the 24 behaviour is just due to
better counters, and maybe the slowdown is just due to a limit check that
never triggered due to 16-bit overflows or something like that..

Linus