Current File : //usr/share/doc/bpftrace/examples/runqlen_example.txt
Demonstrations of runqlen, the Linux BPF/bpftrace version.
This tool samples the length of the CPU scheduler run queues, showing these
sampled lengths as a histogram. This can be used to characterize demand for
CPU resources. For example:
# ./runqlen.bt
Attaching 2 probes...
Sampling run queue length at 99 Hertz... Hit Ctrl-C to end.
^C
@runqlen:
[0, 1) 1967 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
[1, 2) 0 | |
[2, 3) 0 | |
[3, 4) 306 |@@@@@@@@ |
This output shows that the run queue length was usually zero, except for some
samples where it was 3. This was caused by binding 4 CPU bound threads to a
single CPUs.
There is another version of this tool in bcc: https://github.com/iovisor/bcc
The bcc version provides options to customize the output.
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