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diff --git a/Documentation/admin-guide/laptops/laptop-mode.rst b/Documentation/admin-guide/laptops/laptop-mode.rst new file mode 100644 index 0000000000..b61cc601d2 --- /dev/null +++ b/Documentation/admin-guide/laptops/laptop-mode.rst @@ -0,0 +1,770 @@ +=============================================== +How to conserve battery power using laptop-mode +=============================================== + +Document Author: Bart Samwel (bart@samwel.tk) + +Date created: January 2, 2004 + +Last modified: December 06, 2004 + +Introduction +------------ + +Laptop mode is used to minimize the time that the hard disk needs to be spun up, +to conserve battery power on laptops. It has been reported to cause significant +power savings. + +.. Contents + + * Introduction + * Installation + * Caveats + * The Details + * Tips & Tricks + * Control script + * ACPI integration + * Monitoring tool + + +Installation +------------ + +To use laptop mode, you don't need to set any kernel configuration options +or anything. Simply install all the files included in this document, and +laptop mode will automatically be started when you're on battery. For +your convenience, a tarball containing an installer can be downloaded at: + + http://www.samwel.tk/laptop_mode/laptop_mode/ + +To configure laptop mode, you need to edit the configuration file, which is +located in /etc/default/laptop-mode on Debian-based systems, or in +/etc/sysconfig/laptop-mode on other systems. + +Unfortunately, automatic enabling of laptop mode does not work for +laptops that don't have ACPI. On those laptops, you need to start laptop +mode manually. To start laptop mode, run "laptop_mode start", and to +stop it, run "laptop_mode stop". (Note: The laptop mode tools package now +has experimental support for APM, you might want to try that first.) + + +Caveats +------- + +* The downside of laptop mode is that you have a chance of losing up to 10 + minutes of work. If you cannot afford this, don't use it! The supplied ACPI + scripts automatically turn off laptop mode when the battery almost runs out, + so that you won't lose any data at the end of your battery life. + +* Most desktop hard drives have a very limited lifetime measured in spindown + cycles, typically about 50.000 times (it's usually listed on the spec sheet). + Check your drive's rating, and don't wear down your drive's lifetime if you + don't need to. + +* If you mount some of your ext3/reiserfs filesystems with the -n option, then + the control script will not be able to remount them correctly. You must set + DO_REMOUNTS=0 in the control script, otherwise it will remount them with the + wrong options -- or it will fail because it cannot write to /etc/mtab. + +* If you have your filesystems listed as type "auto" in fstab, like I did, then + the control script will not recognize them as filesystems that need remounting. + You must list the filesystems with their true type instead. + +* It has been reported that some versions of the mutt mail client use file access + times to determine whether a folder contains new mail. If you use mutt and + experience this, you must disable the noatime remounting by setting the option + DO_REMOUNT_NOATIME to 0 in the configuration file. + + +The Details +----------- + +Laptop mode is controlled by the knob /proc/sys/vm/laptop_mode. This knob is +present for all kernels that have the laptop mode patch, regardless of any +configuration options. When the knob is set, any physical disk I/O (that might +have caused the hard disk to spin up) causes Linux to flush all dirty blocks. The +result of this is that after a disk has spun down, it will not be spun up +anymore to write dirty blocks, because those blocks had already been written +immediately after the most recent read operation. The value of the laptop_mode +knob determines the time between the occurrence of disk I/O and when the flush +is triggered. A sensible value for the knob is 5 seconds. Setting the knob to +0 disables laptop mode. + +To increase the effectiveness of the laptop_mode strategy, the laptop_mode +control script increases dirty_expire_centisecs and dirty_writeback_centisecs in +/proc/sys/vm to about 10 minutes (by default), which means that pages that are +dirtied are not forced to be written to disk as often. The control script also +changes the dirty background ratio, so that background writeback of dirty pages +is not done anymore. Combined with a higher commit value (also 10 minutes) for +ext3 or ReiserFS filesystems (also done automatically by the control script), +this results in concentration of disk activity in a small time interval which +occurs only once every 10 minutes, or whenever the disk is forced to spin up by +a cache miss. The disk can then be spun down in the periods of inactivity. + + +Configuration +------------- + +The laptop mode configuration file is located in /etc/default/laptop-mode on +Debian-based systems, or in /etc/sysconfig/laptop-mode on other systems. It +contains the following options: + +MAX_AGE: + +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 while you're in laptop mode. + +MINIMUM_BATTERY_MINUTES: + +Automatically disable laptop mode if the remaining number of minutes of +battery power is less than this value. Default is 10 minutes. + +AC_HD/BATT_HD: + +The idle timeout that should be set on your hard drive when laptop mode +is active (BATT_HD) and when it is not active (AC_HD). The defaults are +20 seconds (value 4) for BATT_HD and 2 hours (value 244) for AC_HD. The +possible values are those listed in the manual page for "hdparm" for the +"-S" option. + +HD: + +The devices for which the spindown timeout should be adjusted by laptop mode. +Default is /dev/hda. If you specify multiple devices, separate them by a space. + +READAHEAD: + +Disk readahead, in 512-byte sectors, while laptop mode is active. A large +readahead can prevent disk accesses for things like executable pages (which are +loaded on demand while the application executes) and sequentially accessed data +(MP3s). + +DO_REMOUNTS: + +The control script automatically remounts any mounted journaled filesystems +with appropriate commit interval options. When this option is set to 0, this +feature is disabled. + +DO_REMOUNT_NOATIME: + +When remounting, should the filesystems be remounted with the noatime option? +Normally, this is set to "1" (enabled), but there may be programs that require +access time recording. + +DIRTY_RATIO: + +The percentage of memory that is allowed to contain "dirty" or unsaved data +before a writeback is forced, while laptop mode is active. Corresponds to +the /proc/sys/vm/dirty_ratio sysctl. + +DIRTY_BACKGROUND_RATIO: + +The percentage of memory that is allowed to contain "dirty" or unsaved data +after a forced writeback is done due to an exceeding of DIRTY_RATIO. Set +this nice and low. This corresponds to the /proc/sys/vm/dirty_background_ratio +sysctl. + +Note that the behaviour of dirty_background_ratio is quite different +when laptop mode is active and when it isn't. When laptop mode is inactive, +dirty_background_ratio is the threshold percentage at which background writeouts +start taking place. When laptop mode is active, however, background writeouts +are disabled, and the dirty_background_ratio only determines how much writeback +is done when dirty_ratio is reached. + +DO_CPU: + +Enable CPU frequency scaling when in laptop mode. (Requires CPUFreq to be setup. +See Documentation/admin-guide/pm/cpufreq.rst for more info. Disabled by default.) + +CPU_MAXFREQ: + +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. + + +Tips & Tricks +------------- + +* Bartek Kania reports getting up to 50 minutes of extra battery life (on top + of his regular 3 to 3.5 hours) using a spindown time of 5 seconds (BATT_HD=1). + +* You can spin down the disk while playing MP3, by setting disk readahead + to 8MB (READAHEAD=16384). Effectively, the disk will read a complete MP3 at + once, and will then spin down while the MP3 is playing. (Thanks to Bartek + Kania.) + +* Drew Scott Daniels observed: "I don't know why, but when I decrease the number + of colours that my display uses it consumes less battery power. I've seen + this on powerbooks too. I hope that this is a piece of information that + might be useful to the Laptop Mode patch or its users." + +* In syslog.conf, you can prefix entries with a dash `-` to omit syncing the + file after every logging. When you're using laptop-mode and your disk doesn't + spin down, this is a likely culprit. + +* Richard Atterer observed that laptop mode does not work well with noflushd + (http://noflushd.sourceforge.net/), it seems that noflushd prevents laptop-mode + from doing its thing. + +* If you're worried about your data, you might want to consider using a USB + memory stick or something like that as a "working area". (Be aware though + that flash memory can only handle a limited number of writes, and overuse + may wear out your memory stick pretty quickly. Do _not_ use journalling + filesystems on flash memory sticks.) + + +Configuration file for control and ACPI battery scripts +------------------------------------------------------- + +This allows the tunables to be changed for the scripts via an external +configuration file + +It should be installed as /etc/default/laptop-mode on Debian, and as +/etc/sysconfig/laptop-mode on Red Hat, SUSE, Mandrake, and other work-alikes. + +Config file:: + + # 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 + + +Control script +-------------- + +Please note that this control script works for the Linux 2.4 and 2.6 series (thanks +to Kiko Piris). + +Control script:: + + #!/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 integration +---------------- + +Dax Kelson submitted this so that the ACPI acpid daemon will +kick off the laptop_mode script and run hdparm. The part that +automatically disables laptop mode when the battery is low was +written by Jan Topinski. + +/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 + + +Monitoring tool +--------------- + +Bartek Kania submitted this, it can be used to measure how much time your disk +spends spun up/down. See tools/laptop/dslm/dslm.c |