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Re: Why is my gigabit ethernet so slow?



Martti Kuparinen wrote:

As a reminder, the setup is like this:

S (Ubuntu 9.10) <--> X (NetBSD 5.99.24) <--> R (NetBSD 5.99.24)

I found http://proj.sunet.se/E2E/tcptune.html and played a little with the receiver (NetBSD 5.99.24), below 3 runs with both settings. The conclusion is that I'm happy now as I'm able to route 850+ Mbps through my router...

Step 1
------
(Rebuilt kernel with "options NMBCLUSTERS=16384")
sysctl -w kern.sbmax=8388608
sysctl -w net.inet.tcp.sendspace=3217968
sysctl -w net.inet.tcp.recvspace=3217968
sysctl -w net.inet.tcp.init_win=8

TCP
ttcp-t: 10737418240 bytes in 96.02 real seconds = 853.20 Mbit/sec +++
ttcp-t: 10737418240 bytes in 96.55 real seconds = 848.45 Mbit/sec +++
ttcp-t: 10737418240 bytes in 97.14 real seconds = 843.29 Mbit/sec +++

UDP
ttcp-t: 10737418240 bytes in 93.84 real seconds = 872.95 Mbit/sec +++
ttcp-t: 10737418240 bytes in 93.84 real seconds = 872.94 Mbit/sec +++
ttcp-t: 10737418240 bytes in 93.84 real seconds = 872.96 Mbit/sec +++

Step 2
------

(Reboot and activate all the settings from step 1 and the following two)
sysctl -w net.inet.tcp.sendbuf_max=16777216
sysctl -w net.inet.tcp.recvbuf_max=16777216

TCP
ttcp-t: 10737418240 bytes in 95.92 real seconds = 854.04 Mbit/sec +++
ttcp-t: 10737418240 bytes in 96.80 real seconds = 846.26 Mbit/sec +++
ttcp-t: 10737418240 bytes in 96.54 real seconds = 848.52 Mbit/sec +++

UDP
ttcp-t: 10737418240 bytes in 93.85 real seconds = 872.89 Mbit/sec +++
ttcp-t: 10737418240 bytes in 93.83 real seconds = 873.03 Mbit/sec +++
ttcp-t: 10737418240 bytes in 93.87 real seconds = 872.72 Mbit/sec +++



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