atop cpu idle values are incorrect?

[whitakma]

Binary package hint: atop

Running Ubuntu 9.04, on kernel 2.6.28-16-generic on x86_64.

atop version 1.23-1

I run the command "atop -PCPU,cpu" and get the following output:

...

SEP
CPU ACHILLES 1257866592 2009/11/10 15:23:12 10 100 2 48 77 5 1933 1 4 2 0
cpu ACHILLES 1257866592 2009/11/10 15:23:12 10 100 0 25 21 4 970 0 0 0 0
cpu ACHILLES 1257866592 2009/11/10 15:23:12 10 100 1 24 57 1 962 1 4 2 0
SEP
CPU ACHILLES 1257866602 2009/11/10 15:23:22 10 100 2 64 43 5 2025 0 3 3 0
cpu ACHILLES 1257866602 2009/11/10 15:23:22 10 100 0 12 17 1 994 0 0 1 0
cpu ACHILLES 1257866602 2009/11/10 15:23:22 10 100 1 51 25 3 1031 0 3 3 0
SEP
CPU ACHILLES 1257866612 2009/11/10 15:23:32 10 100 2 55 45 8 1980 0 5 3 0
cpu ACHILLES 1257866612 2009/11/10 15:23:32 10 100 0 26 29 6 957 0 0 0 0
cpu ACHILLES 1257866612 2009/11/10 15:23:32 10 100 1 30 17 2 1024 0 5 2 0
SEP

...

As per default, the interval in the fragment above is 10s.
atop is reporting against a max of 100 clock ticks per sec.

So I always expect to see Idle values < 10*100 = 1000 for an individual core ("cpu" rows) , and < 2000 for both cores added together ("CPU" rows).

In practice there are regular occasions when idle exceeds these limits.

Also I expect to be able to add up the various categories and get 1000 - but I don't seem to be able to come anywhere close...