Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
scheduler(3)		   Erlang Module Definition		  scheduler(3)

NAME
       scheduler - Measure scheduler utilization

DESCRIPTION
       This  module contains utility functions for easier measurement and cal-
       culation	of scheduler utilization, otherwise obtained from calling  the
       more primitive statistics(scheduler_wall_time).

       The simplest usage is to	call scheduler:utilization(Seconds).

DATA TYPES
       sched_sample()

       sched_type() = normal | cpu | io

       sched_id() = integer()

       sched_util_result() =
	   [{sched_type(), sched_id(), float(),	string()} |
	    {total, float(), string()} |
	    {weighted, float(),	string()}]

	      A	list of	tuples containing results for individual schedulers as
	      well as aggregated averages. Util	is the	scheduler  utilization
	      as  a  floating  point value between 0.0 and 1.0.	Percent	is the
	      same utilization as a more human readable	 string	 expressed  in
	      percent.

		{normal, SchedulerId, Util, Percent}:
		  Scheduler  utilization  of  a	 normal	 scheduler with	number
		  SchedulerId.

		{cpu, SchedulerId, Util, Percent}:
		  Scheduler utilization	of a dirty-cpu scheduler  with	number
		  SchedulerId.

		{io, SchedulerId, Util,	Percent}:
		  Scheduler  utilization  of  a	dirty-io scheduler with	number
		  SchedulerId. This tuple will only exist if both samples were
		  taken	with sample_all/0.

		{total,	Util, Percent}:
		  Total	utilization of all normal and dirty-cpu	schedulers.

		{weighted, Util, Percent}:
		  Total	 utilization  of  all normal and dirty-cpu schedulers,
		  weighted against maximum amount of available CPU time.

EXPORTS
       sample()	-> sched_sample()

	      Return a scheduler utilization sample for	normal	and  dirty-cpu
	      schedulers.

       sample_all() -> sched_sample()

	      Return  a	 scheduler  utilization	sample for all schedulers, in-
	      cluding dirty-io schedulers.

       utilization(Seconds) -> sched_util_result()

	      Types:

		 Seconds = integer() >=	1

	      Measure utilization for normal and dirty-cpu  schedulers	during
	      Seconds seconds, and then	return the result.

       utilization(Sample) -> sched_util_result()

	      Types:

		 Sample	= sched_sample()

	      Calculate	scheduler utilizations for the time interval from when
	      Sample was taken and "now". The same as  calling	scheduler:uti-
	      lization(Sample, scheduler:sample_all()).

       utilization(Sample1, Sample2) ->	sched_util_result()

	      Types:

		 Sample1 = Sample2 = sched_sample()

	      Calculates  scheduler utilizations for the time interval between
	      the two samples obtained from calling sample/0 or	sample_all/0.

Ericsson AB		     runtime_tools 1.13.2		  scheduler(3)

NAME | DESCRIPTION | DATA TYPES | EXPORTS

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=scheduler&sektion=3&manpath=FreeBSD+13.0-RELEASE+and+Ports>

home | help