Hi,

There seems to be a problem with the timer resolution on x86_64. This is clear in ping results - I don't know if it's just a ping problem or if it manifests elsewhere as well. It does also affect mtr and traceroute times.

I guess it's more a kernel issue than a CentOS problem, but is anyone else seeing the same?

Ping results have a resolution of 10ms - so a ping <10ms shows as 0.000ms...

--- On an Opteron machine running CentOS-3.4 ---

# uname -a Linux omega.xxx 2.4.21-27.0.2.ELsmp #1 SMP Wed Jan 19 11:28:26 CST 2005 x86_64 x86_64 x86_64 GNU/Linux

# ping 192.168.1.200 PING 192.168.1.200 (192.168.1.200) 56(84) bytes of data. 64 bytes from 192.168.1.200: icmp_seq=0 ttl=64 time=0.000 ms 64 bytes from 192.168.1.200: icmp_seq=1 ttl=64 time=0.000 ms 64 bytes from 192.168.1.200: icmp_seq=2 ttl=64 time=0.000 ms 64 bytes from 192.168.1.200: icmp_seq=3 ttl=64 time=0.000 ms 64 bytes from 192.168.1.200: icmp_seq=4 ttl=64 time=0.000 ms

--- 192.168.1.200 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4000ms rtt min/avg/max/mdev = 0.000/0.000/0.000/0.000 ms, pipe 2

# ping google.com PING google.com (216.239.39.99) 56(84) bytes of data. 64 bytes from 216.239.39.99: icmp_seq=0 ttl=240 time=230 ms 64 bytes from 216.239.39.99: icmp_seq=1 ttl=240 time=220 ms 64 bytes from 216.239.39.99: icmp_seq=2 ttl=240 time=220 ms 64 bytes from 216.239.39.99: icmp_seq=3 ttl=240 time=230 ms 64 bytes from 216.239.39.99: icmp_seq=4 ttl=240 time=230 ms 64 bytes from 216.239.39.99: icmp_seq=5 ttl=240 time=220 ms

--- google.com ping statistics --- 6 packets transmitted, 6 received, 0% packet loss, time 5050ms rtt min/avg/max/mdev = 220.006/225.006/230.006/5.000 ms, pipe 2

---- Expected result: On an i686 machine running CentOS-3.3 ----

# ping 192.168.1.202 PING 192.168.1.202 (192.168.1.202) 56(84) bytes of data. 64 bytes from 192.168.1.202: icmp_seq=0 ttl=64 time=0.094 ms 64 bytes from 192.168.1.202: icmp_seq=1 ttl=64 time=0.059 ms 64 bytes from 192.168.1.202: icmp_seq=2 ttl=64 time=0.070 ms 64 bytes from 192.168.1.202: icmp_seq=3 ttl=64 time=0.057 ms 64 bytes from 192.168.1.202: icmp_seq=4 ttl=64 time=0.068 ms

--- 192.168.1.202 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4016ms rtt min/avg/max/mdev = 0.057/0.069/0.094/0.016 ms, pipe 2

# ping google.com PING google.com (216.239.39.99) 56(84) bytes of data. 64 bytes from 216.239.39.99: icmp_seq=0 ttl=240 time=201 ms 64 bytes from 216.239.39.99: icmp_seq=1 ttl=240 time=203 ms 64 bytes from 216.239.39.99: icmp_seq=2 ttl=240 time=201 ms 64 bytes from 216.239.39.99: icmp_seq=3 ttl=240 time=202 ms 64 bytes from 216.239.39.99: icmp_seq=4 ttl=240 time=201 ms 64 bytes from 216.239.39.99: icmp_seq=5 ttl=240 time=201 ms

--- google.com ping statistics --- 6 packets transmitted, 6 received, 0% packet loss, time 5049ms rtt min/avg/max/mdev = 201.044/201.939/203.012/0.926 ms, pipe 2

Kind regards,

-Simon