2005-09-28 00:29:46

by Justin Piszcz

[permalink] [raw]
Subject: TCP=828mbps, UDP=1mbps? (both running 2.6.13.2)

Any idea why with TCP I get 828 megabits on my gigabit connection but only
1.05 megabits with UDP?

Using iperf to benchmark.

TCP
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[ 4] local 192.168.1.12 port 5001 connected with 192.168.1.253 port
48853
[ 4] 0.0-35.1 sec 3.38 GBytes 828 Mbits/sec


UDP
------------------------------------------------------------
Server listening on UDP port 5001
Receiving 1470 byte datagrams
UDP buffer size: 101 KByte (default)
------------------------------------------------------------
[ 3] local 192.168.1.12 port 5001 connected with 192.168.1.253 port
32773
[ 3] 0.0-10.0 sec 1.25 MBytes 1.05 Mbits/sec 0.043 ms 0/ 893 (0%)


p34:~$ netstat -i
Kernel Interface table
Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR
Flg
eth0 1500 0 1266337 0 0 0 2588651 0 0 0
BMRU
eth1 1500 0 2358 0 0 0 2229 0 0 0
BMRU
eth2 1500 0 39706 0 0 0 5747 0 0 0
BMNRU
lo 16436 0 184 0 0 0 184 0 0 0
LRU

box2:~$ netstat -i
Kernel Interface table
Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR
Flg
eth0 1500 0 2955176 0 0 0 3696501 0 0 0
BMRU
lo 16436 0 612 0 0 0 612 0 0 0
LRU



2005-09-28 09:58:36

by Daniel J Blueman

[permalink] [raw]
Subject: Re: TCP=828mbps, UDP=1mbps? (both running 2.6.13.2)

Justin,

When running iperf in UDP mode (-u), you must specify a bandwidth, ie:

server$ iperf -s -u
client$ iperf -c server -u -b 1000M

Justin Piszcz wrote:
> Any idea why with TCP I get 828 megabits on my gigabit connection but only
> 1.05 megabits with UDP?
>
> Using iperf to benchmark.
>
> TCP
> ------------------------------------------------------------
> Server listening on TCP port 5001
> TCP window size: 85.3 KByte (default)
> ------------------------------------------------------------
> [ 4] local 192.168.1.12 port 5001 connected with 192.168.1.253 port
> 48853
> [ 4] 0.0-35.1 sec 3.38 GBytes 828 Mbits/sec
>
>
> UDP
> ------------------------------------------------------------
> Server listening on UDP port 5001
> Receiving 1470 byte datagrams
> UDP buffer size: 101 KByte (default)
> ------------------------------------------------------------
> [ 3] local 192.168.1.12 port 5001 connected with 192.168.1.253 port
> 32773
> [ 3] 0.0-10.0 sec 1.25 MBytes 1.05 Mbits/sec 0.043 ms 0/ 893 (0%)
>
>
> p34:~$ netstat -i
> Kernel Interface table
> Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR
> Flg
> eth0 1500 0 1266337 0 0 0 2588651 0 0 0
> BMRU
> eth1 1500 0 2358 0 0 0 2229 0 0 0
> BMRU
> eth2 1500 0 39706 0 0 0 5747 0 0 0
> BMNRU
> lo 16436 0 184 0 0 0 184 0 0 0
> LRU
>
> box2:~$ netstat -i
> Kernel Interface table
> Iface MTU Met RX-OK RX-ERR RX-DRP RX-OVR TX-OK TX-ERR TX-DRP TX-OVR
> Flg
> eth0 1500 0 2955176 0 0 0 3696501 0 0 0
> BMRU
> lo 16436 0 612 0 0 0 612 0 0 0
> LRU
___
Daniel J Blueman