Probe Point Identification - Red Hat ENTERPRISE LINUX 5.4 - SYSTEMTAP LANGUAGE Reference Manual

Chapter 9. Predefined functions
qsq_start ("block-write")
}
probe timer.ms(10000) {
exit ()
}
# synthesize queue work/service using three randomized "threads" for each
queue.
global tc
function qs_doit (thread, name) {
n = tc[thread] = (tc[thread]+1) % 3 # per-thread state counter
if (n==1) qs_wait (name)
else if (n==2) qs_run (name)
else if (n==0) qs_done (name)
}
probe timer.ms(100).randomize(100) { qs_doit (0, "block-read") }
probe timer.ms(100).randomize(100) { qs_doit (1, "block-read") }
probe timer.ms(100).randomize(100) { qs_doit (2, "block-read") }
probe timer.ms(100).randomize(100) { qs_doit (3, "block-write") }
probe timer.ms(100).randomize(100) { qs_doit (4, "block-write") }
probe timer.ms(100).randomize(100) { qs_doit (5, "block-write") }
This prints:
block-read: 9 ops/s, 1.090 qlen, 215749 await, 96382 svctm, 69% wait, 64%
util
block-write: 9 ops/s, 0.992 qlen, 208485 await, 103150 svctm, 69% wait, 61%
util
block-read: 9 ops/s, 0.968 qlen, 197411 await, 97762 svctm, 63% wait, 63%
util
block-write: 8 ops/s, 0.930 qlen, 202414 await, 93870 svctm, 60% wait, 56%
util
block-read: 8 ops/s, 0.774 qlen, 192957 await, 99995 svctm, 58% wait, 62%
util
block-write: 9 ops/s, 0.861 qlen, 193857 await, 101573 svctm, 56% wait, 64%
util

9.7. Probe point identification

The following functions help you identify probe points.
9.7.1. pp
General syntax:
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