如何使用笔记本模式节约电池电量¶
文档作者: Bart Samwel (bart@samwel.tk)
创建日期: 2004年1月2日
最后修改: 2004年12月6日
简介¶
笔记本模式旨在最大限度地减少硬盘启动所需的时间，以节约笔记本电脑的电池电量。据报道，它能显著节约电量。
安装¶
要使用笔记本模式，您无需设置任何内核配置选项。只需安装本文档中包含的所有文件，当您使用电池供电时，笔记本模式将自动启动。为了您的方便，包含安装程序的 tar 包可从以下地址下载：
要配置笔记本模式，您需要编辑配置文件，该文件在基于 Debian 的系统上位于 /etc/default/laptop-mode，在其他系统上位于 /etc/sysconfig/laptop-mode。
不幸的是，对于不具备 ACPI 的笔记本电脑，笔记本模式的自动启用功能不起作用。在这些笔记本电脑上，您需要手动启动笔记本模式。要启动笔记本模式，运行“laptop_mode start”，要停止它，运行“laptop_mode stop”。（注意：笔记本模式工具包现在已实验性支持 APM，您可能想先尝试一下。）
注意事项¶
笔记本模式的缺点是您有可能丢失长达 10 分钟的工作内容。如果您无法承受这种损失，请不要使用它！提供的 ACPI 脚本在电池电量几乎耗尽时会自动关闭笔记本模式，这样您就不会在电池寿命结束时丢失任何数据。
大多数台式机硬盘的寿命（以主轴停转周期衡量）非常有限，通常约为 50,000 次（这通常列在规格表中）。检查您硬盘的额定值，如果您不需要，请不要缩短硬盘的寿命。
如果您使用 -n 选项挂载了部分 ext3/reiserfs 文件系统，则控制脚本将无法正确地重新挂载它们。您必须在控制脚本中设置 DO_REMOUNTS=0，否则它将使用错误的选项重新挂载它们——或者因为它无法写入 /etc/mtab 而失败。
如果您的文件系统在 fstab 中被列为“auto”类型（就像我曾经那样），那么控制脚本将不会识别它们为需要重新挂载的文件系统。您必须改为列出文件系统的实际类型。
据报道，某些版本的 mutt 邮件客户端会使用文件访问时间来判断文件夹是否包含新邮件。如果您使用 mutt 并遇到此问题，则必须通过在配置文件中将选项 DO_REMOUNT_NOATIME 设置为 0 来禁用 noatime 重新挂载。
详情¶
笔记本模式由 /proc/sys/vm/laptop_mode 旋钮控制。所有打有笔记本模式补丁的内核都存在此旋钮，无论任何配置选项如何。当此旋钮设置后，任何物理磁盘 I/O（可能导致硬盘启动）都会使 Linux 刷新所有脏块。其结果是，硬盘在停转后将不再因为写入脏块而启动，因为这些脏块在最近的读取操作之后就已经立即写入了。laptop_mode 旋钮的值决定了磁盘 I/O 发生与刷新触发之间的时间。该旋钮的合理值为 5 秒。将此旋钮设置为 0 会禁用笔记本模式。
为了提高 laptop_mode 策略的效率，laptop_mode 控制脚本会将 /proc/sys/vm 中的 dirty_expire_centisecs 和 dirty_writeback_centisecs 增加到大约 10 分钟（默认），这意味着脏页不会被迫频繁地写入磁盘。控制脚本还会改变脏背景比率，这样脏页的后台回写就不再执行了。结合 ext3 或 ReiserFS 文件系统的更高提交值（同样是 10 分钟，也由控制脚本自动完成），这将导致磁盘活动集中在一个短时间间隔内，每 10 分钟只发生一次，或者当磁盘因缓存未命中而被强制启动时发生。然后，磁盘可以在不活动期间停转。
配置¶
笔记本模式配置文件在基于 Debian 的系统上位于 /etc/default/laptop-mode，在其他系统上位于 /etc/sysconfig/laptop-mode。它包含以下选项：
MAX_AGE
您可接受的硬盘停转最长时间（以秒为单位）。最坏的情况下，如果您的电池在笔记本模式下发生故障，您可能会丢失这段时间的工作内容。
MINIMUM_BATTERY_MINUTES
如果电池剩余电量低于此值，则自动禁用笔记本模式。默认值为 10 分钟。
AC_HD/BATT_HD
在笔记本模式激活时 (BATT_HD) 和非激活时 (AC_HD) 应设置的硬盘空闲超时时间。BATT_HD 的默认值为 20 秒（值 4），AC_HD 的默认值为 2 小时（值 244）。可能的值是“hdparm”手册页中“ -S”选项所列出的值。
HD
笔记本模式应调整停转超时时间的设备。默认值为 /dev/hda。如果您指定多个设备，请用空格分隔。
READAHEAD
笔记本模式激活时，磁盘预读量，以 512 字节扇区为单位。较大的预读量可以防止对可执行页面（应用程序执行时按需加载）和顺序访问数据（如 MP3 文件）进行磁盘访问。
DO_REMOUNTS
控制脚本会自动重新挂载所有已挂载的日志文件系统，并使用适当的提交间隔选项。当此选项设置为 0 时，此功能被禁用。
DO_REMOUNT_NOATIME
重新挂载时，文件系统是否应使用 noatime 选项重新挂载？通常，此选项设置为“1”（启用），但有些程序可能需要记录访问时间。
DIRTY_RATIO
笔记本模式激活时，在强制回写之前允许包含“脏”或未保存数据的内存百分比。对应于 /proc/sys/vm/dirty_ratio sysctl。
DIRTY_BACKGROUND_RATIO
由于超出 DIRTY_RATIO 而强制回写之后，允许包含“脏”或未保存数据的内存百分比。请将其设置得较低。这对应于 /proc/sys/vm/dirty_background_ratio sysctl。
请注意，当笔记本模式处于活动状态和非活动状态时，dirty_background_ratio 的行为会大相径庭。当笔记本模式非活动时，dirty_background_ratio 是后台写入开始发生的阈值百分比。然而，当笔记本模式激活时，后台写入被禁用，dirty_background_ratio 只决定当达到 dirty_ratio 时完成多少回写。
DO_CPU
在笔记本模式下启用 CPU 频率缩放。（需要设置 CPUFreq。有关更多信息，请参阅CPU 性能缩放。默认禁用。）
CPU_MAXFREQ
当使用电池供电时，系统应使用的最大 CPU 速度是多少？合法值为“slowest”（指 CPU 能够运行的最低速度），或 /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies 中列出的值。
提示与技巧¶
Bartek Kania 报告称，通过使用 5 秒的停转时间 (BATT_HD=1)，他额外获得了长达 50 分钟的电池续航时间（在他常规的 3 到 3.5 小时基础上）。
您可以在播放 MP3 时让磁盘停转，方法是将磁盘预读设置为 8MB (READAHEAD=16384)。实际上，磁盘将一次性读取整个 MP3 文件，然后在 MP3 播放时停转。（鸣谢 Bartek Kania。）
Drew Scott Daniels 观察到：“我不知道为什么，但是当我减少显示器使用的颜色数量时，它会消耗更少的电池电量。我在 Powerbook 上也见过这种情况。我希望这条信息对笔记本模式补丁或其用户有用。”
在 syslog.conf 中，您可以在条目前加上一个短划线 -，以省略每次日志记录后同步文件。当您使用笔记本模式且硬盘无法停转时，这很可能就是原因。
Richard Atterer 观察到笔记本模式与 noflushd (http://noflushd.sourceforge.net/) 配合不佳，似乎 noflushd 阻止了笔记本模式正常工作。
如果您担心数据安全，您可能需要考虑使用 USB 存储棒或类似设备作为“工作区”。（但请注意，闪存只能处理有限次数的写入，过度使用可能会很快耗尽您的存储棒寿命。切勿在闪存棒上使用日志文件系统。）
控制脚本和 ACPI 电池脚本的配置文件¶
这允许通过外部配置文件更改脚本的可调参数
在 Debian 上应将其安装为 /etc/default/laptop-mode，在 Red Hat、SUSE、Mandrake 及其他类似系统上应安装为 /etc/sysconfig/laptop-mode。
配置文件
# Maximum time, in seconds, of hard drive spindown time that you are
# comfortable with. Worst case, it's possible that you could lose this
# amount of work if your battery fails you while in laptop mode.
#MAX_AGE=600
# Automatically disable laptop mode when the number of minutes of battery
# that you have left goes below this threshold.
MINIMUM_BATTERY_MINUTES=10
# Read-ahead, in 512-byte sectors. You can spin down the disk while playing MP3/OGG
# by setting the disk readahead to 8MB (READAHEAD=16384). Effectively, the disk
# will read a complete MP3 at once, and will then spin down while the MP3/OGG is
# playing.
#READAHEAD=4096
# Shall we remount journaled fs. with appropriate commit interval? (1=yes)
#DO_REMOUNTS=1
# And shall we add the "noatime" option to that as well? (1=yes)
#DO_REMOUNT_NOATIME=1
# Dirty synchronous ratio. At this percentage of dirty pages the process
# which
# calls write() does its own writeback
#DIRTY_RATIO=40
#
# Allowed dirty background ratio, in percent. Once DIRTY_RATIO has been
# exceeded, the kernel will wake flusher threads which will then reduce the
# amount of dirty memory to dirty_background_ratio. Set this nice and low,
# so once some writeout has commenced, we do a lot of it.
#
#DIRTY_BACKGROUND_RATIO=5
# kernel default dirty buffer age
#DEF_AGE=30
#DEF_UPDATE=5
#DEF_DIRTY_BACKGROUND_RATIO=10
#DEF_DIRTY_RATIO=40
#DEF_XFS_AGE_BUFFER=15
#DEF_XFS_SYNC_INTERVAL=30
#DEF_XFS_BUFD_INTERVAL=1
# This must be adjusted manually to the value of HZ in the running kernel
# on 2.4, until the XFS people change their 2.4 external interfaces to work in
# centisecs. This can be automated, but it's a work in progress that still
# needs# some fixes. On 2.6 kernels, XFS uses USER_HZ instead of HZ for
# external interfaces, and that is currently always set to 100. So you don't
# need to change this on 2.6.
#XFS_HZ=100
# Should the maximum CPU frequency be adjusted down while on battery?
# Requires CPUFreq to be setup.
# See Documentation/admin-guide/pm/cpufreq.rst for more info
#DO_CPU=0
# When on battery what is the maximum CPU speed that the system should
# use? Legal values are "slowest" for the slowest speed that your
# CPU is able to operate at, or a value listed in:
# /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
# Only applicable if DO_CPU=1.
#CPU_MAXFREQ=slowest
# Idle timeout for your hard drive (man hdparm for valid values, -S option)
# Default is 2 hours on AC (AC_HD=244) and 20 seconds for battery (BATT_HD=4).
#AC_HD=244
#BATT_HD=4
# The drives for which to adjust the idle timeout. Separate them by a space,
# e.g. HD="/dev/hda /dev/hdb".
#HD="/dev/hda"
# Set the spindown timeout on a hard drive?
#DO_HD=1
控制脚本¶
请注意，此控制脚本适用于 Linux 2.4 和 2.6 系列（鸣谢 Kiko Piris）。
控制脚本
#!/bin/bash
# start or stop laptop_mode, best run by a power management daemon when
# ac gets connected/disconnected from a laptop
#
# install as /sbin/laptop_mode
#
# Contributors to this script: Kiko Piris
# Bart Samwel
# Micha Feigin
# Andrew Morton
# Herve Eychenne
# Dax Kelson
#
# Original Linux 2.4 version by: Jens Axboe
#############################################################################
# Source config
if [ -f /etc/default/laptop-mode ] ; then
# Debian
. /etc/default/laptop-mode
elif [ -f /etc/sysconfig/laptop-mode ] ; then
# Others
. /etc/sysconfig/laptop-mode
fi
# Don't raise an error if the config file is incomplete
# set defaults instead:
# Maximum time, in seconds, of hard drive spindown time that you are
# comfortable with. Worst case, it's possible that you could lose this
# amount of work if your battery fails you while in laptop mode.
MAX_AGE=${MAX_AGE:-'600'}
# Read-ahead, in kilobytes
READAHEAD=${READAHEAD:-'4096'}
# Shall we remount journaled fs. with appropriate commit interval? (1=yes)
DO_REMOUNTS=${DO_REMOUNTS:-'1'}
# And shall we add the "noatime" option to that as well? (1=yes)
DO_REMOUNT_NOATIME=${DO_REMOUNT_NOATIME:-'1'}
# Shall we adjust the idle timeout on a hard drive?
DO_HD=${DO_HD:-'1'}
# Adjust idle timeout on which hard drive?
HD="${HD:-'/dev/hda'}"
# spindown time for HD (hdparm -S values)
AC_HD=${AC_HD:-'244'}
BATT_HD=${BATT_HD:-'4'}
# Dirty synchronous ratio. At this percentage of dirty pages the process which
# calls write() does its own writeback
DIRTY_RATIO=${DIRTY_RATIO:-'40'}
# cpu frequency scaling
# See Documentation/admin-guide/pm/cpufreq.rst for more info
DO_CPU=${CPU_MANAGE:-'0'}
CPU_MAXFREQ=${CPU_MAXFREQ:-'slowest'}
#
# Allowed dirty background ratio, in percent. Once DIRTY_RATIO has been
# exceeded, the kernel will wake flusher threads which will then reduce the
# amount of dirty memory to dirty_background_ratio. Set this nice and low,
# so once some writeout has commenced, we do a lot of it.
#
DIRTY_BACKGROUND_RATIO=${DIRTY_BACKGROUND_RATIO:-'5'}
# kernel default dirty buffer age
DEF_AGE=${DEF_AGE:-'30'}
DEF_UPDATE=${DEF_UPDATE:-'5'}
DEF_DIRTY_BACKGROUND_RATIO=${DEF_DIRTY_BACKGROUND_RATIO:-'10'}
DEF_DIRTY_RATIO=${DEF_DIRTY_RATIO:-'40'}
DEF_XFS_AGE_BUFFER=${DEF_XFS_AGE_BUFFER:-'15'}
DEF_XFS_SYNC_INTERVAL=${DEF_XFS_SYNC_INTERVAL:-'30'}
DEF_XFS_BUFD_INTERVAL=${DEF_XFS_BUFD_INTERVAL:-'1'}
# This must be adjusted manually to the value of HZ in the running kernel
# on 2.4, until the XFS people change their 2.4 external interfaces to work in
# centisecs. This can be automated, but it's a work in progress that still needs
# some fixes. On 2.6 kernels, XFS uses USER_HZ instead of HZ for external
# interfaces, and that is currently always set to 100. So you don't need to
# change this on 2.6.
XFS_HZ=${XFS_HZ:-'100'}
#############################################################################
KLEVEL="$(uname -r |
{
IFS='.' read a b c
echo $a.$b
}
)"
case "$KLEVEL" in
"2.4"|"2.6")
;;
*)
echo "Unhandled kernel version: $KLEVEL ('uname -r' = '$(uname -r)')" >&2
exit 1
;;
esac
if [ ! -e /proc/sys/vm/laptop_mode ] ; then
echo "Kernel is not patched with laptop_mode patch." >&2
exit 1
fi
if [ ! -w /proc/sys/vm/laptop_mode ] ; then
echo "You do not have enough privileges to enable laptop_mode." >&2
exit 1
fi
# Remove an option (the first parameter) of the form option=<number> from
# a mount options string (the rest of the parameters).
parse_mount_opts () {
OPT="$1"
shift
echo ",$*," | sed \
-e 's/,'"$OPT"'=[0-9]*,/,/g' \
-e 's/,,*/,/g' \
-e 's/^,//' \
-e 's/,$//'
}
# Remove an option (the first parameter) without any arguments from
# a mount option string (the rest of the parameters).
parse_nonumber_mount_opts () {
OPT="$1"
shift
echo ",$*," | sed \
-e 's/,'"$OPT"',/,/g' \
-e 's/,,*/,/g' \
-e 's/^,//' \
-e 's/,$//'
}
# Find out the state of a yes/no option (e.g. "atime"/"noatime") in
# fstab for a given filesystem, and use this state to replace the
# value of the option in another mount options string. The device
# is the first argument, the option name the second, and the default
# value the third. The remainder is the mount options string.
#
# Example:
# parse_yesno_opts_wfstab /dev/hda1 atime atime defaults,noatime
#
# If fstab contains, say, "rw" for this filesystem, then the result
# will be "defaults,atime".
parse_yesno_opts_wfstab () {
L_DEV="$1"
OPT="$2"
DEF_OPT="$3"
shift 3
L_OPTS="$*"
PARSEDOPTS1="$(parse_nonumber_mount_opts $OPT $L_OPTS)"
PARSEDOPTS1="$(parse_nonumber_mount_opts no$OPT $PARSEDOPTS1)"
# Watch for a default atime in fstab
FSTAB_OPTS="$(awk '$1 == "'$L_DEV'" { print $4 }' /etc/fstab)"
if echo "$FSTAB_OPTS" | grep "$OPT" > /dev/null ; then
# option specified in fstab: extract the value and use it
if echo "$FSTAB_OPTS" | grep "no$OPT" > /dev/null ; then
echo "$PARSEDOPTS1,no$OPT"
else
# no$OPT not found -- so we must have $OPT.
echo "$PARSEDOPTS1,$OPT"
fi
else
# option not specified in fstab -- choose the default.
echo "$PARSEDOPTS1,$DEF_OPT"
fi
}
# Find out the state of a numbered option (e.g. "commit=NNN") in
# fstab for a given filesystem, and use this state to replace the
# value of the option in another mount options string. The device
# is the first argument, and the option name the second. The
# remainder is the mount options string in which the replacement
# must be done.
#
# Example:
# parse_mount_opts_wfstab /dev/hda1 commit defaults,commit=7
#
# If fstab contains, say, "commit=3,rw" for this filesystem, then the
# result will be "rw,commit=3".
parse_mount_opts_wfstab () {
L_DEV="$1"
OPT="$2"
shift 2
L_OPTS="$*"
PARSEDOPTS1="$(parse_mount_opts $OPT $L_OPTS)"
# Watch for a default commit in fstab
FSTAB_OPTS="$(awk '$1 == "'$L_DEV'" { print $4 }' /etc/fstab)"
if echo "$FSTAB_OPTS" | grep "$OPT=" > /dev/null ; then
# option specified in fstab: extract the value, and use it
echo -n "$PARSEDOPTS1,$OPT="
echo ",$FSTAB_OPTS," | sed \
-e 's/.*,'"$OPT"'=//' \
-e 's/,.*//'
else
# option not specified in fstab: set it to 0
echo "$PARSEDOPTS1,$OPT=0"
fi
}
deduce_fstype () {
MP="$1"
# My root filesystem unfortunately has
# type "unknown" in /etc/mtab. If we encounter
# "unknown", we try to get the type from fstab.
cat /etc/fstab |
grep -v '^#' |
while read FSTAB_DEV FSTAB_MP FSTAB_FST FSTAB_OPTS FSTAB_DUMP FSTAB_DUMP ; do
if [ "$FSTAB_MP" = "$MP" ]; then
echo $FSTAB_FST
exit 0
fi
done
}
if [ $DO_REMOUNT_NOATIME -eq 1 ] ; then
NOATIME_OPT=",noatime"
fi
case "$1" in
start)
AGE=$((100*$MAX_AGE))
XFS_AGE=$(($XFS_HZ*$MAX_AGE))
echo -n "Starting laptop_mode"
if [ -d /proc/sys/vm/pagebuf ] ; then
# (For 2.4 and early 2.6.)
# This only needs to be set, not reset -- it is only used when
# laptop mode is enabled.
echo $XFS_AGE > /proc/sys/vm/pagebuf/lm_flush_age
echo $XFS_AGE > /proc/sys/fs/xfs/lm_sync_interval
elif [ -f /proc/sys/fs/xfs/lm_age_buffer ] ; then
# (A couple of early 2.6 laptop mode patches had these.)
# The same goes for these.
echo $XFS_AGE > /proc/sys/fs/xfs/lm_age_buffer
echo $XFS_AGE > /proc/sys/fs/xfs/lm_sync_interval
elif [ -f /proc/sys/fs/xfs/age_buffer ] ; then
# (2.6.6)
# But not for these -- they are also used in normal
# operation.
echo $XFS_AGE > /proc/sys/fs/xfs/age_buffer
echo $XFS_AGE > /proc/sys/fs/xfs/sync_interval
elif [ -f /proc/sys/fs/xfs/age_buffer_centisecs ] ; then
# (2.6.7 upwards)
# And not for these either. These are in centisecs,
# not USER_HZ, so we have to use $AGE, not $XFS_AGE.
echo $AGE > /proc/sys/fs/xfs/age_buffer_centisecs
echo $AGE > /proc/sys/fs/xfs/xfssyncd_centisecs
echo 3000 > /proc/sys/fs/xfs/xfsbufd_centisecs
fi
case "$KLEVEL" in
"2.4")
echo 1 > /proc/sys/vm/laptop_mode
echo "30 500 0 0 $AGE $AGE 60 20 0" > /proc/sys/vm/bdflush
;;
"2.6")
echo 5 > /proc/sys/vm/laptop_mode
echo "$AGE" > /proc/sys/vm/dirty_writeback_centisecs
echo "$AGE" > /proc/sys/vm/dirty_expire_centisecs
echo "$DIRTY_RATIO" > /proc/sys/vm/dirty_ratio
echo "$DIRTY_BACKGROUND_RATIO" > /proc/sys/vm/dirty_background_ratio
;;
esac
if [ $DO_REMOUNTS -eq 1 ]; then
cat /etc/mtab | while read DEV MP FST OPTS DUMP PASS ; do
PARSEDOPTS="$(parse_mount_opts "$OPTS")"
if [ "$FST" = 'unknown' ]; then
FST=$(deduce_fstype $MP)
fi
case "$FST" in
"ext3"|"reiserfs")
PARSEDOPTS="$(parse_mount_opts commit "$OPTS")"
mount $DEV -t $FST $MP -o remount,$PARSEDOPTS,commit=$MAX_AGE$NOATIME_OPT
;;
"xfs")
mount $DEV -t $FST $MP -o remount,$OPTS$NOATIME_OPT
;;
esac
if [ -b $DEV ] ; then
blockdev --setra $(($READAHEAD * 2)) $DEV
fi
done
fi
if [ $DO_HD -eq 1 ] ; then
for THISHD in $HD ; do
/sbin/hdparm -S $BATT_HD $THISHD > /dev/null 2>&1
/sbin/hdparm -B 1 $THISHD > /dev/null 2>&1
done
fi
if [ $DO_CPU -eq 1 -a -e /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq ]; then
if [ $CPU_MAXFREQ = 'slowest' ]; then
CPU_MAXFREQ=`cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq`
fi
echo $CPU_MAXFREQ > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
fi
echo "."
;;
stop)
U_AGE=$((100*$DEF_UPDATE))
B_AGE=$((100*$DEF_AGE))
echo -n "Stopping laptop_mode"
echo 0 > /proc/sys/vm/laptop_mode
if [ -f /proc/sys/fs/xfs/age_buffer -a ! -f /proc/sys/fs/xfs/lm_age_buffer ] ; then
# These need to be restored, if there are no lm_*.
echo $(($XFS_HZ*$DEF_XFS_AGE_BUFFER)) > /proc/sys/fs/xfs/age_buffer
echo $(($XFS_HZ*$DEF_XFS_SYNC_INTERVAL)) > /proc/sys/fs/xfs/sync_interval
elif [ -f /proc/sys/fs/xfs/age_buffer_centisecs ] ; then
# These need to be restored as well.
echo $((100*$DEF_XFS_AGE_BUFFER)) > /proc/sys/fs/xfs/age_buffer_centisecs
echo $((100*$DEF_XFS_SYNC_INTERVAL)) > /proc/sys/fs/xfs/xfssyncd_centisecs
echo $((100*$DEF_XFS_BUFD_INTERVAL)) > /proc/sys/fs/xfs/xfsbufd_centisecs
fi
case "$KLEVEL" in
"2.4")
echo "30 500 0 0 $U_AGE $B_AGE 60 20 0" > /proc/sys/vm/bdflush
;;
"2.6")
echo "$U_AGE" > /proc/sys/vm/dirty_writeback_centisecs
echo "$B_AGE" > /proc/sys/vm/dirty_expire_centisecs
echo "$DEF_DIRTY_RATIO" > /proc/sys/vm/dirty_ratio
echo "$DEF_DIRTY_BACKGROUND_RATIO" > /proc/sys/vm/dirty_background_ratio
;;
esac
if [ $DO_REMOUNTS -eq 1 ] ; then
cat /etc/mtab | while read DEV MP FST OPTS DUMP PASS ; do
# Reset commit and atime options to defaults.
if [ "$FST" = 'unknown' ]; then
FST=$(deduce_fstype $MP)
fi
case "$FST" in
"ext3"|"reiserfs")
PARSEDOPTS="$(parse_mount_opts_wfstab $DEV commit $OPTS)"
PARSEDOPTS="$(parse_yesno_opts_wfstab $DEV atime atime $PARSEDOPTS)"
mount $DEV -t $FST $MP -o remount,$PARSEDOPTS
;;
"xfs")
PARSEDOPTS="$(parse_yesno_opts_wfstab $DEV atime atime $OPTS)"
mount $DEV -t $FST $MP -o remount,$PARSEDOPTS
;;
esac
if [ -b $DEV ] ; then
blockdev --setra 256 $DEV
fi
done
fi
if [ $DO_HD -eq 1 ] ; then
for THISHD in $HD ; do
/sbin/hdparm -S $AC_HD $THISHD > /dev/null 2>&1
/sbin/hdparm -B 255 $THISHD > /dev/null 2>&1
done
fi
if [ $DO_CPU -eq 1 -a -e /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq ]; then
echo `cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq` > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
fi
echo "."
;;
*)
echo "Usage: $0 {start|stop}" 2>&1
exit 1
;;
esac
exit 0
ACPI 集成¶
Dax Kelson 提交了此内容，以便 ACPI acpid 守护程序能够启动 laptop_mode 脚本并运行 hdparm。电池电量低时自动禁用笔记本模式的部分由 Jan Topinski 编写。
/etc/acpi/events/ac_adapter
event=ac_adapter
action=/etc/acpi/actions/ac.sh %e
/etc/acpi/events/battery
event=battery.*
action=/etc/acpi/actions/battery.sh %e
/etc/acpi/actions/ac.sh
#!/bin/bash
# ac on/offline event handler
status=`awk '/^state: / { print $2 }' /proc/acpi/ac_adapter/$2/state`
case $status in
"on-line")
/sbin/laptop_mode stop
exit 0
;;
"off-line")
/sbin/laptop_mode start
exit 0
;;
esac
/etc/acpi/actions/battery.sh
#! /bin/bash
# Automatically disable laptop mode when the battery almost runs out.
BATT_INFO=/proc/acpi/battery/$2/state
if [[ -f /proc/sys/vm/laptop_mode ]]
then
LM=`cat /proc/sys/vm/laptop_mode`
if [[ $LM -gt 0 ]]
then
if [[ -f $BATT_INFO ]]
then
# Source the config file only now that we know we need
if [ -f /etc/default/laptop-mode ] ; then
# Debian
. /etc/default/laptop-mode
elif [ -f /etc/sysconfig/laptop-mode ] ; then
# Others
. /etc/sysconfig/laptop-mode
fi
MINIMUM_BATTERY_MINUTES=${MINIMUM_BATTERY_MINUTES:-'10'}
ACTION="`cat $BATT_INFO | grep charging | cut -c 26-`"
if [[ ACTION -eq "discharging" ]]
then
PRESENT_RATE=`cat $BATT_INFO | grep "present rate:" | sed "s/.* \([0-9][0-9]* \).*/\1/" `
REMAINING=`cat $BATT_INFO | grep "remaining capacity:" | sed "s/.* \([0-9][0-9]* \).*/\1/" `
fi
if (($REMAINING * 60 / $PRESENT_RATE < $MINIMUM_BATTERY_MINUTES))
then
/sbin/laptop_mode stop
fi
else
logger -p daemon.warning "You are using laptop mode and your battery interface $BATT_INFO is missing. This may lead to loss of data when the battery runs out. Check kernel ACPI support and /proc/acpi/battery folder, and edit /etc/acpi/battery.sh to set BATT_INFO to the correct path."
fi
fi
fi
监控工具¶
Bartek Kania 提交了此工具，可用于衡量您的磁盘启动/停转的时间。请参阅 tools/laptop/dslm/dslm.c