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loadrec(1)		FreeBSD	General	Commands Manual		    loadrec(1)

NAME
     loadrec --	CPU load recorder

SYNOPSIS
     loadrec -h
     loadrec [-v] [-d ival] [-p	ival] [-o file]

DESCRIPTION
     The loadrec command performs a recording of the current load. The purpose
     is	to reproduce this load to test different powerd(8) and powerd++(8)
     configurations under identical load conditions using loadplay(1).

   ARGUMENTS
     The following argument types can be given:

     ival    A time interval can be given in seconds or	milliseconds.
		   s, ms
	     An	interval without a unit	is treated as milliseconds.

     file    A file name.

   OPTIONS
     The following options are supported:

     -h, --help
	     Show usage	and exit.

     -v, --verbose
	     Be	verbose	and produce initial diagnostics	on stderr.

     -d, --duration ival
	     The duration of the recording session, defaults to	30 seconds.

     -p, --poll	ival
	     The polling interval to take load samples at, defaults to 25 mil-
	     liseconds.

     -o, --output file
	     The output	file to	write the load to.

USAGE NOTES
     To	create reproducible results set	a fixed	CPU frequency below the
     threshold at which	the turbo mode is activated. E.g. an Intel(R) Core(TM)
     i7-4500U CPU supports the following frequency settings:

	 > sysctl dev.cpu.0.freq_levels
	 dev.cpu.0.freq_levels:	2401/15000 2400/15000 2300/14088 2200/13340 2000/11888 1900/11184 1800/10495 1700/9680 1500/8372 1400/7738 1300/7119 1200/6511 1100/5789 900/4643 800/4090 768/3550

     Supposedly	the first mode,	which is off by	1 MHz, invokes the turbo mode.
     However all modes down to 1800 MHz	actually invoke	the turbo mode for
     this model. The only way to determine this	is by benchmarking the step-
     pings to find out that there is a huge performance	step between 1700 and
     1800 MHz and that all the modes above 1700	MHz show the exact same	per-
     formance (given similar thermal conditions).

     So	in order to produce a usable measurement for this CPU the clock	needs
     to	be set to 1700 MHz or lower (higher is better to be able to record a
     wider range of loads):

	 # service powerd++ stop
	 Stopping powerdxx.
	 Waiting for PIDS: 63574.
	 # powerd++ -M1700

     Run loadrec for a brief time to test it:

	 > loadrec -d.25s
	 usr.app.powerdxx.loadrec.features=1
	 hw.machine=amd64
	 hw.model=Intel(R) Core(TM) i7-4500U CPU @ 1.80GHz
	 hw.ncpu=4
	 hw.acpi.acline=1
	 dev.cpu.0.freq=768
	 dev.cpu.0.freq_levels=2401/15000 2400/15000 2300/14088	2200/13340 2000/11888 1900/11184 1800/10495 1700/9680 1500/8372	1400/7738 1300/7119 1200/6511 1100/5789	900/4643 800/4090 768/3550
	 0 768 768 768 768 728001 0 278439 54957 10215972 753315 0 245117 7838 10270972	767662 0 241991	37110 10230545 772745 0	235729 10307 10258490
	 25 768	768 768	768 0 0	0 0 3 2	0 0 0 1	0 0 0 0	3 0 0 0	0 4
	 25 768	768 768	768 0 0	0 0 3 1	0 0 0 2	0 0 0 0	3 1 0 0	0 2
	 25 768	768 768	768 0 0	1 0 2 1	0 2 0 0	0 0 0 0	3 0 0 1	0 2
	 25 768	768 768	768 3 0	0 0 1 1	0 2 0 1	1 0 3 0	0 2 0 2	0 0
	 25 768	768 768	768 0 0	0 0 3 0	0 1 0 2	0 0 0 0	3 3 0 0	0 0
	 25 768	768 768	768 0 0	0 0 3 0	0 0 0 3	0 0 0 0	3 2 0 1	0 0
	 25 768	768 768	768 0 0	0 0 3 0	0 0 0 3	0 0 0 0	3 2 0 1	0 0
	 25 768	768 768	768 2 0	0 0 1 1	0 1 0 1	0 0 2 0	1 2 0 1	0 0
	 25 768	768 768	768 0 0	0 0 4 1	0 2 0 1	0 0 0 0	4 0 0 1	0 2
	 25 768	768 768	768 0 0	0 0 3 2	0 1 0 0	0 0 0 0	3 0 0 0	0 4

     Printing the load creates significant load	itself,	so for the actual mea-
     surement the output should	be written to a	file. Create your workload and
     start your	measurement:

	 > loadrec -o video-session.load

     On	the example setup loadrec produces a load of 0.001 (i.e. 0.1%),	so its
     effect on the measurement is negligible.

SEE ALSO
     cpufreq(4), loadplay(1), powerd(8), powerd++(8), sysctl(8)

AUTHORS
     Implementation and	manual by Dominic Fandrey <kami@freebsd.org>

FreeBSD	13.0		       4 February, 2019			  FreeBSD 13.0

NAME | SYNOPSIS | DESCRIPTION | USAGE NOTES | SEE ALSO | AUTHORS

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