smtoff revision 1.2 
1#!/bin/sh
2#
3# $NetBSD: smtoff,v 1.2 2019/05/12 00:24:03 kre Exp $
4#
5# Public Domain.
6#
7
8# PROVIDE: smtoff
9# REQUIRE: root bootconf mountcritlocal tty
10
11$_rc_subr_loaded . /etc/rc.subr
12
13name="smtoff"
14rcvar=$name
15
16start_cmd="smtoff_start"
17stop_cmd="smtoff_stop"
18
19# ------------------------------------------------------------------------------
20
21#
22# The format of the output is:
23#
24#     ...
25#     cpu0: SMT ID 1
26#     ...
27#
28# Return the value.
29#
30GetSmtId() {
31	cpuctl identify "$1" |
32	while read cpuN smt id N junk
33	do
34		test -n "$junk" && continue
35
36		case "${smt} ${id}" in
37		'SMT ID')
38			case "$N" in
39			[0-9]|[1-9][0-9]|[1-9][0-9]*[0-9])
40				printf %s "$N"
41				return
42				;;
43			esac
44			;;
45		esac
46	done
47	printf "error"
48}
49
50#
51# The format of the output (without -n) would be:
52#
53#     hw.ncpu = 80
54#
55# so use -n to make life easy
56#
57# Return the value.
58#
59CountCPUs() {
60	sysctl -n hw.ncpu
61}
62
63# ------------------------------------------------------------------------------
64
65#
66# Disable SMT. We skip cpu0.
67#
68smtoff_start()
69{
70	ncpus=$(CountCPUs)
71	i=1
72
73	while [ "$i" -lt "$ncpus" ]
74	do
75		smtid=$(GetSmtId "$i" 2>/dev/null)
76
77		case "$smtid" in
78		error)			# Didn't get the ID? Then maybe no SMT.
79			;;
80
81		0)			# The first thread is never disabled.
82			;;
83
84		*)
85			cpuctl offline "$i"
86			;;
87		esac
88
89		i=$(($i+1))
90	done
91}
92
93#
94# Enable SMT. We basically turn on each CPU.
95#
96smtoff_stop()
97{
98	ncpus=$(CountCPUs)
99	i=1
100
101	while [ "$i" -lt "$ncpus" ]
102	do
103		cpuctl online "$i"
104		i=$(($i+1))
105	done
106}
107
108load_rc_config $name
109run_rc_command "$1"
110