Hi,

We are running on 5.5 on a HP ProLiant DL360 G6. Kernel version is 2.6.18-194.17.1.el5 (we had also tested with the latest available kernel kernel-2.6.18-238.1.1.el5.x86_64)

We running some performance tests using the "iperf" utility.

We are seeing very bad and inconsistent performance on the UDP testing.

The maximum we could get, was 440 Mbits/sec, and it varies from 250 to 440 Mbits/sec.

That hurts. So, what speed do you get using TCP? You should really get almost wire speed with TCP, so I expect to be the same with UDP. I'm usually testing raw TCP transfers with mbuffer listening on one side and piping data to in using bash on the other side, like 'cat /dev/null > /dev/tcp/host/port'

BTW, I have never used iperf, but is it sane to run it via strace? It will for sure slow things down.

Simon

We are connected on a 1000Mb/s link, we also tested the same using a cross-over connections between the two machines, but the same performance.

We also see a lot of dropped UDP packets.

Udp: 551522838 packets received 1902 packets to unknown port received. 109709802 packet receive errors 7239 packets sent

We had checked all the kernel configurations and set them as recommended.

This is the settings and tests we have done

Server: net.core.rmem_default = 2097152 net.core.wmem_default = 2097152 net.core.rmem_max = 8388608 net.core.wmem_max = 8388608 strace -fttt -o /tmp/server.trace iperf -s -u -p 2222 -w 6m -i 5 -l 1k

Client: net.core.rmem_default = 2097152 net.core.wmem_default = 2097152 net.core.rmem_max = 8388608 net.core.wmem_max = 8388608 strace -fttt -o /tmp/client.trace iperf -p 2222 -u -w 6m -i 5 -t 60 -c 192.168.1.2 -b 990M -l 1k

Can someone please help me with this, since I am running in circles and can't get the required UDP performance?

-- Prasad Pillarisetti "If everything is coming your way, then you are in the wrong lane" _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos