FM / tapset

/usr/share/systemtap/tapset

Name	Size	Mode	Actions
arm/	-	0755	rm
arm64/	-	0755	rm
bpf/	-	0755	rm
dyninst/	-	0755	rm
i386/	-	0755	rm
ia64/	-	0755	rm
linux/	-	0755	rm
mips/	-	0755	rm
powerpc/	-	0755	rm
riscv/	-	0755	rm
s390/	-	0755	rm
x86_64/	-	0755	rm
ansi.stp	4178	0644	edit dl rm
argv.stp	2721	0644	edit dl rm
choose_defined.stpm	208	0644	edit dl rm
container_of.stpm	235	0644	edit dl rm
context.stp	6103	0644	edit dl rm
errno.stp	9118	0644	edit dl rm
floatingpoint.stp	6936	0644	edit dl rm
indent-default.stp	59	0644	edit dl rm
indent.stp	4590	0644	edit dl rm
init.stp	269	0644	edit dl rm
input.stp	263	0644	edit dl rm
java.stp	1346	0644	edit dl rm
libperl5.26.3-64.stp	1339	0644	edit dl rm
libpython2.7-64.stp	522	0644	edit dl rm
livepatch.stp	3006	0644	edit dl rm
logging.stp	4132	0644	edit dl rm
macros.stpm	562	0644	edit dl rm
null.stp	17	0644	edit dl rm
offsetof.stpm	183	0644	edit dl rm
oneshot.stp	38	0644	edit dl rm
pn.stp	1588	0644	edit dl rm
print_stats.stpm	1719	0644	edit dl rm
private30.stpm	80	0644	edit dl rm
prometheus.stp	129	0644	edit dl rm
prometheus.stpm	8380	0644	edit dl rm
python.stp	474	0644	edit dl rm
python2.stp	29435	0644	edit dl rm
python3.stp	36655	0644	edit dl rm
queue_stats.stp	9487	0644	edit dl rm
random.stp	432	0644	edit dl rm
README	371	0644	edit dl rm
regex.stp	4107	0644	edit dl rm
registers.stp	11081	0644	edit dl rm
sizeof.stpm	212	0644	edit dl rm
speculative.stp	1746	0644	edit dl rm
sreg_arch.stpm	263	0644	edit dl rm
stap_staticmarkers.stp	9670	0644	edit dl rm
stopwatch.stp	3063	0644	edit dl rm
string.stp	7514	0644	edit dl rm
switchfile.stp	612	0644	edit dl rm
system.stp	593	0644	edit dl rm
this.stp	160	0644	edit dl rm
timers.stp	924	0644	edit dl rm
tls.stp	8099	0644	edit dl rm
tokenize.stp	2124	0644	edit dl rm
try_assign.stpm	768	0644	edit dl rm
type_defined.stpm	374	0644	edit dl rm
tzinfo.stp	930	0644	edit dl rm
uconversions-guru.stp	6078	0644	edit dl rm
uconversions.stp	36640	0644	edit dl rm

Edit: /usr/share/systemtap/tapset/queue_stats.stp (9487B)

# qstats.stp: Queue statistics gathering tapset
/* <tapsetdescription>
 * The queue_stats tapset provides functions that,
 * given notifications of elementary queuing events (wait, run, done),
 * tracks averages such as queue length, service and wait times,
 * utilization.
 * 
 * The functions qs_wait(), qs_run(), and qs_done() should be called
 * from appropriate probes, in sequence.
 * 
 * Functions with the prefix qsq_ are for querying the statistics averaged
 * since the first queue operation (or when qsq_start() was called).
 * Since statistics are often fractional, a scale parameter is used to
 * multiply the result to a more useful scale. For some fractions, a scale
 * of 100 will usefully return percentage numbers.
 * </tapsetdescription>
 */

# ------------------------------------------------------------------------

# The default timing function: microseconds.  This function could
# go into a separate file (say, qstats_qs_time.stp), so that a user
# script can override it with another definition.

/* XXX: docstring */
function qs_time () { return gettimeofday_us () }

# ------------------------------------------------------------------------

@__private30 global qs_wtime, qs_wlentime, qs_wcount
@__private30 global qs_rtime, qs_rlentime, qs_rcount
@__private30 global qs_stime, qs_utime, qs_dcount

# ------------------------------------------------------------------------

@__private30 function _qs_update (qname) {
  now = qs_time ()
  then = qs_utime[qname]; if (! then) { then = now }
  delta = now-then

qs_wtime[qname] += qs_wcount[qname] ? delta : 0
  qs_wlentime[qname] += qs_wcount[qname] * delta
  qs_rtime[qname] += qs_rcount[qname] ? delta : 0
  qs_rlentime[qname] += qs_rcount[qname] * delta
  qs_utime[qname] = now  
}

/**
 * sfunction qs_wait - Function to record enqueue requests
 * @qname: the name of the queue requesting enqueue
 *
 * Description: This function records that a new request
 * was enqueued for the given queue name.
 */
function qs_wait (qname:string) { # enqueueing request
   _qs_update (qname)
   qs_wcount[qname] ++
}

/**
 * sfunction qs_run - Function to record being moved from wait queue to being serviced 
 * @qname: the name of the service being moved and started 
 *
 * Description: This function records that the previous enqueued
 * request was removed from the given wait queue and is now 
 * being serviced. 
 */
function qs_run (qname:string) { # starting to service request
  _qs_update (qname)
  if (qs_wcount[qname] > 0) {
    qs_wcount[qname] --
    qs_rcount[qname] ++
  }
}

/**
 * sfunction qs_done - Function to record finishing request 
 * @qname: the name of the service that finished 
 *
 * Description: This function records that a request 
 * originally from the given queue has completed being 
 * serviced.
 */
function qs_done (qname:string) { # done servicing request
  _qs_update (qname)
  if (qs_rcount[qname] > 0) {
    qs_rcount[qname] --
    qs_dcount[qname] ++
  }
}

# ------------------------------------------------------------------------

/**
 * sfunction qsq_start - Function to reset the stats for a queue
 * @qname: the name of the service that finished 
 *
 * Description: This function resets the statistics counters for the given
 * queue, and restarts tracking from the moment the function was called.
 * This function is also used to create intialize a queue.
 */
function qsq_start (qname:string) {  # reset statistics for new baseline
  qs_rcount[qname] = 0
  delete qs_rtime[qname]
  delete qs_rlentime[qname]
  qs_wcount[qname] = 0
  delete qs_wtime[qname]
  delete qs_wlentime[qname]
  delete qs_dcount[qname]
  delete qs_utime[qname]
  qs_stime[qname] = qs_time ()
}

# ------------------------------------------------------------------------
# Various query functions.  Each returns the average, taken over the time
# interval from the last qsq_start().  Most deal with fractions, and so
# also take a scale parameter (use 100 for percent).

/**
 * sfunction qsq_utilization - Fraction of time that any request was being serviced 
 * @qname: queue name
 * @scale: scale variable to take account for interval fraction
 *
 * Description: This function returns the average time in microseconds
 * that at least one request was being serviced. 
 */
function qsq_utilization:long (qname:string, scale:long) {
  _qs_update (qname)
  elapsed = qs_time() - qs_stime[qname]
  return (scale * qs_rtime[qname]) / elapsed
}

# fraction of time that any request was blocked in the wait queue

/**
 * sfunction qsq_blocked - Returns the time reqest was on the wait queue 
 * @qname: queue name
 * @scale: scale variable to take account for interval fraction
 *
 * Description: This function returns the fraction of elapsed time during
 * which one or more requests were on the wait queue.
 */
function qsq_blocked:long (qname:string, scale:long) {
  _qs_update (qname)
  elapsed = qs_time() - qs_stime[qname]
  return (scale * qs_wtime[qname]) / elapsed
}

# length of wait queue 
/**
 * sfunction qsq_wait_queue_length - length of wait queue 
 * @qname: queue name
 * @scale: scale variable to take account for interval fraction
 *
 * Description: This function returns the average length of the wait queue 
 */
function qsq_wait_queue_length:long (qname:string, scale:long) {
  _qs_update (qname)
  elapsed = qs_time() - qs_stime[qname]
  return (scale * qs_wlentime[qname]) / elapsed
}

/**
 * sfunction qsq_service_time - Amount of time per request service 
 * @qname: queue name
 * @scale: scale variable to take account for interval fraction
 *
 * Description: This function returns the average time in microseconds
 * required to service a request once it is removed from the wait queue.
 */
function qsq_service_time:long (qname:string, scale:long) {
  _qs_update (qname)
  return (scale * qs_rlentime[qname]) / qs_dcount[qname]
}

/**
 * sfunction qsq_wait_time - Amount of time in queue + service per request
 * @qname: queue name
 * @scale: scale variable to take account for interval fraction
 *
 * Description: This function returns the average time in microseconds
 * that it took for a request to be serviced (qs_wait() to qa_done()).
 */
function qsq_wait_time:long (qname:string, scale:long) {
  _qs_update (qname)
  return (scale * (qs_rlentime[qname] + qs_wlentime[qname]))
    / qs_dcount[qname]
}

/**
 * sfunction qsq_throughput - Number of requests served per unit time 
 * @qname: queue name
 * @scale: scale variable to take account for interval fraction
 *
 * Description: This function returns the average number or requests
 * served per microsecond. 
 */
function qsq_throughput:long (qname:string, scale:long) {
  _qs_update (qname)
  elapsed = qs_time() - qs_stime[qname]
  return (scale * qs_dcount[qname]) / elapsed
}

# ------------------------------------------------------------------------

/**
 * sfunction qsq_print - Prints a line of statistics for the given queue
 * @qname: queue name
 *
 * Description: This function prints a line containing the following
 * statistics for the given queue:
 * the queue name, 
 * the average rate of requests per second,
 * the average wait queue length,
 * the average time on the wait queue,
 * the average time to service a request,
 * the percentage of time the wait queue was used, 
 * and the percentage of time request was being serviced.
 */
function qsq_print (qname:string) {
  qt = qsq_throughput (qname, 1000000000) # 1000 * (number of requests served per second)
  qwl = qsq_wait_queue_length (qname, 1000)
  printf("%s: %d.%03d ops/s, %d.%03d qlen, %d await, %d svctm, %d%% wait, %d%% util\n",
    qname,
    qt/1000, qt%1000,
    qwl/1000, qwl%1000,
    qsq_wait_time (qname, 1),
    qsq_service_time (qname, 1),
    qsq_blocked (qname, 100),
    qsq_utilization (qname, 100))
}

/* What follows in an example form 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")
 * 	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, 0.744 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
 */

cmd: