Linux – Check ping statistics without stopping

The last value, labeled mdev under Linux and stddev under Solaris is computed slightly differently depending on these OSes.

The formula used by Linux ping is:

sqrt(smean-mean²)

while the one used by Solaris ping is:

sqrt((smean-mean²)*received/received-1)

with smean being the mean of rtt squares, mean the mean of rtt values and received the number of answers received.

Here is a small awk program using your data and showing how are computed these values.

echo "1.91 2.83 4.41 1.83 2.98 2.18 2.15 1.68 2.30 2.04 1.64 1.98 1.69 1.88
1.91 1.83 1.70 2.00 2.03 1.89 2.36 2.12 2.07 1.91 1.84 2.04 2.05 2.10 2.19
2.22 1.94 2.13 1.98 2.08 1.62 3.29 2.17 1.99 2.38 2.55 2.16 1.90 1.92 1.90
2.89 2.04 2.05 2.12 2.18 1.61 2.08 1.90 2.17 3.01 1.84 2.12 20.9 362 2.07
2.31 2.42 2.05 2.47 2.55 2.13 2.56 2.07 468 2.33 2.32 1.93 1.87 2.50 1.82
2.45 1.95" | awk '
function abs(v) {return v < 0 ? -v : v}
BEGIN {
  min=0x7fffffff;
}
{
  for(i=0;i<NF;i++) {
    received++
    v=$i
    min=v<min?v:min;
    max=v>max?v:max;
    sum+=v
    sum2+=v*v
  }
}
END {
  mean=sum/received
  smean=sum2/received
  printf("received=%d, min=%f, avg=%f, max=%f\n",received,min,sum/received,max)
  printf("Linux ping mdev: %f\n", sqrt(smean-(mean*mean)))
  printf("Solaris ping stddev: %f\n", sqrt(((smean-(mean*mean))*received)/(received-1)))
}
'

Its output is consistent with your test:

received=76, min=1.610000, avg=13.294211, max=468.000000
Linux ping mdev: 66.632781
Solaris ping stddev: 67.075529

The time statistic is the total time spent sending and receiving echo packets, including the delay between each packet:

$ time ping 127.0.0.1
PING 127.0.0.1 (127.0.0.1) 56(84) bytes of data.
64 bytes from 127.0.0.1: icmp_seq=1 ttl=64 time=0.049 ms
64 bytes from 127.0.0.1: icmp_seq=2 ttl=64 time=0.039 ms
64 bytes from 127.0.0.1: icmp_seq=3 ttl=64 time=0.039 ms
^C
--- 127.0.0.1 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 1998ms
rtt min/avg/max/mdev = 0.039/0.042/0.049/0.007 ms

real    0m2.362s
user    0m0.000s
sys 0m0.000s