tcp mem vector of 3 integers

$cat /proc/sys/net/ipv4/tcp_mem
40704	54272	81408
$
tcp_mem

 vector of 3 INTEGERs: min, pressure, max
min: below this number of pages TCP is not bothered about its memory appetite.

pressure: when amount of memory allocated by TCP exceeds this
number of pages, TCP moderates its memory consumption and
 enters memory pressure mode, which is exited when memory
 consumption fall  under "min".

max: number of pages allowed for queueing by all TCP sockets.
Defaults are calculated at boot time from amount of available
memory.
net/ipv4/tcp_input.c - 11 identical

   308:   (int)tp->rcv_ssthresh < tcp_space(sk) &&
   309:   !tcp_memory_pressure) {
   310:       int incr;

   391:   !tcp_memory_pressure &&
   392:   atomic_read(&tcp_memory_allocated)  /proc/sys/net/ipv/tcp_mem

33:

luotao1130.googlecode.com/svn - Unknown - Shell

"IV CONFIGURATION"

a selection follows ...

The ideal TCP window size is approximately equal to
the bandwidth-delay product. For some of the
experiments, the window size required is higher than the
default allowed by Linux. To be able to use the proper
window sizes required for the experiments, the TCP
buffers must be tuned. The five Linux configuration
values tcp_mem, tcp_rmem, tcp_wmem, wmem_max
and rmem_max must be modified to accommodate the
higher window sizes. This is done by executing the
following commands on both the sender and the
receiver.
echo “48128 48640 49152” >
/proc/sys/net/ipv4/tcp_mem
echo 4096 33554432 33554432 >
/proc/sys/net/ipv4/tcp_rmem
echo 4096 33554432 33554432 >
/proc/sys/net/ipv4/tcp_wmem
echo “33554432” > /proc/sys/net/core/wmem_max
echo “33554432” > /proc/sys/net/core/rmem_max

source :

Implementing a Testbed for the Evaluation of
FAST TCP in DOCSIS-based
Access Networks
David Kennedy and Irena Atov
Centre for Advanced Internet Architectures. Technical Report 060119A
Swinburne University of Technology
Melbourne, Australia
{dkennedy,iatov}@swin.edu.au