Qsq_Utilization; Qsq_Wait_Queue_Length; Qsq_Wait_Time; A Queue Example - Red Hat ENTERPRISE LINUX 5.4 - SYSTEMTAP LANGUAGE Reference Manual

qsq_utilization

qsq_throughput:long (qname:string, scale:long)
This function returns the average number of requests served per microsecond.
9.6.6. qsq_utilization
General syntax:
qsq_utilization:long (qname:string, scale:long)
This function returns the average time in microseconds that at least one request was being serviced.

9.6.7. qsq_wait_queue_length

General syntax:
qsq_wait_queue_length:long (qname:string, scale:long)
This function returns the average length of the wait queue.

9.6.8. qsq_wait_time

General syntax:
qsq_wait_time:long (qname:string, scale:long)
This function returns the average time in microseconds that it took for a request to be serviced
(qs_wait() to qs_done()).

9.6.9. A queue example

What follows is an example from src/testsuite/systemtap.samples/queue_demo.stp. It uses the
randomize feature of the timer probe to simulate queuing activity.
probe begin {
qsq_start ("block-read")
qsq_start ("block-write")
}
probe timer.ms(3500), end {
qsq_print ("block-read")
qsq_start ("block-read")
qsq_print ("block-write")
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