Hist_Log - Red Hat ENTERPRISE LINUX 5.4 - SYSTEMTAP LANGUAGE Reference Manual

8.4.2. @hist_log

The statement @hist_log(v) represents a base-2 logarithmic histogram. Empty buckets are
replaced with a tilde (~) character in the same way as @hist_linear() (see above).
The following is an example.
global reads
probe netdev.receive {
reads <<< length
}
probe end {
print(@hist_log(reads))
}
This generates the following output.
value |-------------------------------------------------- count
8 |
16 |
32 |
64 |
128 |
256 |
512 |
1024 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@ 16689
2048 |
4096 |
@hist_log
0
0
254
3
2
2
4
0
0
37