Re: sack

From: David S. Miller (
Date: Thu Jan 13 2000 - 01:06:37 EST

   Date: Wed, 12 Jan 2000 13:34:34 -0800 (PST)
   From: Sandeep Agarwal <>

   I am trying to change see what is the effect of tcp processing by
   turning off SACK. Is there a socket layer option for this or do i
   have to change sysctl_tcp_sack to off. Is there any other way to do
   this - maybe that would save me more code processing.

There is no socket level option to turn off SACK.
Setting the sysctl to "0" is the only way to turn it off,
and the effect is global.

Actually, the effect is global for "new" connections.
Old connections, created before SACK was turned off,
which have negotiated to use SACK, will continue to do
so. Therefore you could do something silly like:

1) Make connection with SACK, pause
2) sysctl_tcp_sack = "0"
3) Make connection without SACK
4) Run benchmark

For testing purposes.

David S. Miller
To unsubscribe from this list: send the line "unsubscribe linux-net" in
the body of a message to

This archive was generated by hypermail 2b29 : Sat Jan 15 2000 - 21:00:29 EST