NetBSD/etc/rc.d/smtoff

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#!/bin/sh
#
# $NetBSD: smtoff,v 1.6 2020/09/08 12:52:18 martin Exp $
#
# Public Domain.
#
# PROVIDE: smtoff
# REQUIRE: root bootconf CRITLOCALMOUNTED tty
$_rc_subr_loaded . /etc/rc.subr
name="smtoff"
rcvar=$name
start_cmd="smtoff_start"
stop_cmd="smtoff_stop"
# ------------------------------------------------------------------------------
#
# The format of the output is:
#
# ...
# cpu0: SMT ID 1
# ...
#
# Return the value.
#
GetSmtId() {
cpuctl identify "$1" |
while read cpuN smt id N junk
do
test -n "$junk" && continue
case "${smt} ${id}" in
'SMT ID')
case "$N" in
[0-9]|[1-9][0-9]|[1-9][0-9]*[0-9])
printf %s "$N"
return
;;
esac
;;
esac
done
}
CountCPUs() {
sysctl -n hw.ncpu
}
# ------------------------------------------------------------------------------
#
# Disable SMT. We skip cpu0.
#
smtoff_start()
{
ncpus=$(CountCPUs)
i=1
while [ "$i" -lt "$ncpus" ]
do
smtid=$(GetSmtId "$i" 2>/dev/null)
case "$smtid" in
'') # Didn't get the ID? Then maybe no SMT.
;;
0) # The first thread is never disabled.
;;
*)
cpuctl offline "$i"
;;
esac
i=$(($i+1))
done
}
#
# Enable SMT. We basically turn on each CPU.
#
smtoff_stop()
{
ncpus=$(CountCPUs)
i=1
while [ "$i" -lt "$ncpus" ]
do
cpuctl online "$i"
i=$(($i+1))
done
}
load_rc_config $name
run_rc_command "$1"