linux/Documentation/laptops/laptop-mode.txt
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   1How to conserve battery power using laptop-mode
   2-----------------------------------------------
   3
   4Document Author: Bart Samwel (bart@samwel.tk)
   5Date created: January 2, 2004
   6Last modified: December 06, 2004
   7
   8Introduction
   9------------
  10
  11Laptop mode is used to minimize the time that the hard disk needs to be spun up,
  12to conserve battery power on laptops. It has been reported to cause significant
  13power savings.
  14
  15Contents
  16--------
  17
  18* Introduction
  19* Installation
  20* Caveats
  21* The Details
  22* Tips & Tricks
  23* Control script
  24* ACPI integration
  25* Monitoring tool
  26
  27
  28Installation
  29------------
  30
  31To use laptop mode, you don't need to set any kernel configuration options
  32or anything. Simply install all the files included in this document, and
  33laptop mode will automatically be started when you're on battery. For
  34your convenience, a tarball containing an installer can be downloaded at:
  35
  36http://www.samwel.tk/laptop_mode/laptop_mode/
  37
  38To configure laptop mode, you need to edit the configuration file, which is
  39located in /etc/default/laptop-mode on Debian-based systems, or in
  40/etc/sysconfig/laptop-mode on other systems.
  41
  42Unfortunately, automatic enabling of laptop mode does not work for
  43laptops that don't have ACPI. On those laptops, you need to start laptop
  44mode manually. To start laptop mode, run "laptop_mode start", and to
  45stop it, run "laptop_mode stop". (Note: The laptop mode tools package now
  46has experimental support for APM, you might want to try that first.)
  47
  48
  49Caveats
  50-------
  51
  52* The downside of laptop mode is that you have a chance of losing up to 10
  53  minutes of work. If you cannot afford this, don't use it! The supplied ACPI
  54  scripts automatically turn off laptop mode when the battery almost runs out,
  55  so that you won't lose any data at the end of your battery life.
  56
  57* Most desktop hard drives have a very limited lifetime measured in spindown
  58  cycles, typically about 50.000 times (it's usually listed on the spec sheet).
  59  Check your drive's rating, and don't wear down your drive's lifetime if you
  60  don't need to.
  61
  62* If you mount some of your ext3/reiserfs filesystems with the -n option, then
  63  the control script will not be able to remount them correctly. You must set
  64  DO_REMOUNTS=0 in the control script, otherwise it will remount them with the
  65  wrong options -- or it will fail because it cannot write to /etc/mtab.
  66
  67* If you have your filesystems listed as type "auto" in fstab, like I did, then
  68  the control script will not recognize them as filesystems that need remounting.
  69  You must list the filesystems with their true type instead.
  70
  71* It has been reported that some versions of the mutt mail client use file access
  72  times to determine whether a folder contains new mail. If you use mutt and
  73  experience this, you must disable the noatime remounting by setting the option
  74  DO_REMOUNT_NOATIME to 0 in the configuration file.
  75
  76
  77The Details
  78-----------
  79
  80Laptop mode is controlled by the knob /proc/sys/vm/laptop_mode. This knob is
  81present for all kernels that have the laptop mode patch, regardless of any
  82configuration options. When the knob is set, any physical disk I/O (that might
  83have caused the hard disk to spin up) causes Linux to flush all dirty blocks. The
  84result of this is that after a disk has spun down, it will not be spun up
  85anymore to write dirty blocks, because those blocks had already been written
  86immediately after the most recent read operation. The value of the laptop_mode
  87knob determines the time between the occurrence of disk I/O and when the flush
  88is triggered. A sensible value for the knob is 5 seconds. Setting the knob to
  890 disables laptop mode.
  90
  91To increase the effectiveness of the laptop_mode strategy, the laptop_mode
  92control script increases dirty_expire_centisecs and dirty_writeback_centisecs in
  93/proc/sys/vm to about 10 minutes (by default), which means that pages that are
  94dirtied are not forced to be written to disk as often. The control script also
  95changes the dirty background ratio, so that background writeback of dirty pages
  96is not done anymore. Combined with a higher commit value (also 10 minutes) for
  97ext3 or ReiserFS filesystems (also done automatically by the control script),
  98this results in concentration of disk activity in a small time interval which
  99occurs only once every 10 minutes, or whenever the disk is forced to spin up by
 100a cache miss. The disk can then be spun down in the periods of inactivity.
 101
 102If you want to find out which process caused the disk to spin up, you can
 103gather information by setting the flag /proc/sys/vm/block_dump. When this flag
 104is set, Linux reports all disk read and write operations that take place, and
 105all block dirtyings done to files. This makes it possible to debug why a disk
 106needs to spin up, and to increase battery life even more. The output of
 107block_dump is written to the kernel output, and it can be retrieved using
 108"dmesg". When you use block_dump and your kernel logging level also includes
 109kernel debugging messages, you probably want to turn off klogd, otherwise
 110the output of block_dump will be logged, causing disk activity that is not
 111normally there.
 112
 113
 114Configuration
 115-------------
 116
 117The laptop mode configuration file is located in /etc/default/laptop-mode on
 118Debian-based systems, or in /etc/sysconfig/laptop-mode on other systems. It
 119contains the following options:
 120
 121MAX_AGE:
 122
 123Maximum time, in seconds, of hard drive spindown time that you are
 124comfortable with. Worst case, it's possible that you could lose this
 125amount of work if your battery fails while you're in laptop mode.
 126
 127MINIMUM_BATTERY_MINUTES:
 128
 129Automatically disable laptop mode if the remaining number of minutes of
 130battery power is less than this value. Default is 10 minutes.
 131
 132AC_HD/BATT_HD:
 133
 134The idle timeout that should be set on your hard drive when laptop mode
 135is active (BATT_HD) and when it is not active (AC_HD). The defaults are
 13620 seconds (value 4) for BATT_HD  and 2 hours (value 244) for AC_HD. The
 137possible values are those listed in the manual page for "hdparm" for the
 138"-S" option.
 139
 140HD:
 141
 142The devices for which the spindown timeout should be adjusted by laptop mode.
 143Default is /dev/hda. If you specify multiple devices, separate them by a space.
 144
 145READAHEAD:
 146
 147Disk readahead, in 512-byte sectors, while laptop mode is active. A large
 148readahead can prevent disk accesses for things like executable pages (which are
 149loaded on demand while the application executes) and sequentially accessed data
 150(MP3s).
 151
 152DO_REMOUNTS:
 153
 154The control script automatically remounts any mounted journaled filesystems
 155with appropriate commit interval options. When this option is set to 0, this
 156feature is disabled.
 157
 158DO_REMOUNT_NOATIME:
 159
 160When remounting, should the filesystems be remounted with the noatime option?
 161Normally, this is set to "1" (enabled), but there may be programs that require
 162access time recording.
 163
 164DIRTY_RATIO:
 165
 166The percentage of memory that is allowed to contain "dirty" or unsaved data
 167before a writeback is forced, while laptop mode is active. Corresponds to
 168the /proc/sys/vm/dirty_ratio sysctl.
 169
 170DIRTY_BACKGROUND_RATIO:
 171
 172The percentage of memory that is allowed to contain "dirty" or unsaved data
 173after a forced writeback is done due to an exceeding of DIRTY_RATIO. Set
 174this nice and low. This corresponds to the /proc/sys/vm/dirty_background_ratio
 175sysctl.
 176
 177Note that the behaviour of dirty_background_ratio is quite different
 178when laptop mode is active and when it isn't. When laptop mode is inactive,
 179dirty_background_ratio is the threshold percentage at which background writeouts
 180start taking place. When laptop mode is active, however, background writeouts
 181are disabled, and the dirty_background_ratio only determines how much writeback
 182is done when dirty_ratio is reached.
 183
 184DO_CPU:
 185
 186Enable CPU frequency scaling when in laptop mode. (Requires CPUFreq to be setup.
 187See Documentation/cpu-freq/user-guide.txt for more info. Disabled by default.)
 188
 189CPU_MAXFREQ:
 190
 191When on battery, what is the maximum CPU speed that the system should use? Legal
 192values are "slowest" for the slowest speed that your CPU is able to operate at,
 193or a value listed in /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies.
 194
 195
 196Tips & Tricks
 197-------------
 198
 199* Bartek Kania reports getting up to 50 minutes of extra battery life (on top
 200  of his regular 3 to 3.5 hours) using a spindown time of 5 seconds (BATT_HD=1).
 201
 202* You can spin down the disk while playing MP3, by setting disk readahead
 203  to 8MB (READAHEAD=16384). Effectively, the disk will read a complete MP3 at
 204  once, and will then spin down while the MP3 is playing. (Thanks to Bartek
 205  Kania.)
 206
 207* Drew Scott Daniels observed: "I don't know why, but when I decrease the number
 208  of colours that my display uses it consumes less battery power. I've seen
 209  this on powerbooks too. I hope that this is a piece of information that
 210  might be useful to the Laptop Mode patch or its users."
 211
 212* In syslog.conf, you can prefix entries with a dash ``-'' to omit syncing the
 213  file after every logging. When you're using laptop-mode and your disk doesn't
 214  spin down, this is a likely culprit.
 215
 216* Richard Atterer observed that laptop mode does not work well with noflushd
 217  (http://noflushd.sourceforge.net/), it seems that noflushd prevents laptop-mode
 218  from doing its thing.
 219
 220* If you're worried about your data, you might want to consider using a USB
 221  memory stick or something like that as a "working area". (Be aware though
 222  that flash memory can only handle a limited number of writes, and overuse
 223  may wear out your memory stick pretty quickly. Do _not_ use journalling
 224  filesystems on flash memory sticks.)
 225
 226
 227Configuration file for control and ACPI battery scripts
 228-------------------------------------------------------
 229
 230This allows the tunables to be changed for the scripts via an external
 231configuration file
 232
 233It should be installed as /etc/default/laptop-mode on Debian, and as
 234/etc/sysconfig/laptop-mode on Red Hat, SUSE, Mandrake, and other work-alikes.
 235
 236--------------------CONFIG FILE BEGIN-------------------------------------------
 237# Maximum time, in seconds, of hard drive spindown time that you are
 238# comfortable with. Worst case, it's possible that you could lose this
 239# amount of work if your battery fails you while in laptop mode.
 240#MAX_AGE=600
 241
 242# Automatically disable laptop mode when the number of minutes of battery
 243# that you have left goes below this threshold.
 244MINIMUM_BATTERY_MINUTES=10
 245
 246# Read-ahead, in 512-byte sectors. You can spin down the disk while playing MP3/OGG
 247# by setting the disk readahead to 8MB (READAHEAD=16384). Effectively, the disk
 248# will read a complete MP3 at once, and will then spin down while the MP3/OGG is
 249# playing.
 250#READAHEAD=4096
 251
 252# Shall we remount journaled fs. with appropriate commit interval? (1=yes)
 253#DO_REMOUNTS=1
 254
 255# And shall we add the "noatime" option to that as well? (1=yes)
 256#DO_REMOUNT_NOATIME=1
 257
 258# Dirty synchronous ratio.  At this percentage of dirty pages the process
 259# which
 260# calls write() does its own writeback
 261#DIRTY_RATIO=40
 262
 263#
 264# Allowed dirty background ratio, in percent.  Once DIRTY_RATIO has been
 265# exceeded, the kernel will wake flusher threads which will then reduce the
 266# amount of dirty memory to dirty_background_ratio.  Set this nice and low,
 267# so once some writeout has commenced, we do a lot of it.
 268#
 269#DIRTY_BACKGROUND_RATIO=5
 270
 271# kernel default dirty buffer age
 272#DEF_AGE=30
 273#DEF_UPDATE=5
 274#DEF_DIRTY_BACKGROUND_RATIO=10
 275#DEF_DIRTY_RATIO=40
 276#DEF_XFS_AGE_BUFFER=15
 277#DEF_XFS_SYNC_INTERVAL=30
 278#DEF_XFS_BUFD_INTERVAL=1
 279
 280# This must be adjusted manually to the value of HZ in the running kernel
 281# on 2.4, until the XFS people change their 2.4 external interfaces to work in
 282# centisecs. This can be automated, but it's a work in progress that still
 283# needs# some fixes. On 2.6 kernels, XFS uses USER_HZ instead of HZ for
 284# external interfaces, and that is currently always set to 100. So you don't
 285# need to change this on 2.6.
 286#XFS_HZ=100
 287
 288# Should the maximum CPU frequency be adjusted down while on battery?
 289# Requires CPUFreq to be setup.
 290# See Documentation/cpu-freq/user-guide.txt for more info
 291#DO_CPU=0
 292
 293# When on battery what is the maximum CPU speed that the system should
 294# use? Legal values are "slowest" for the slowest speed that your
 295# CPU is able to operate at, or a value listed in:
 296# /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
 297# Only applicable if DO_CPU=1.
 298#CPU_MAXFREQ=slowest
 299
 300# Idle timeout for your hard drive (man hdparm for valid values, -S option)
 301# Default is 2 hours on AC (AC_HD=244) and 20 seconds for battery (BATT_HD=4).
 302#AC_HD=244
 303#BATT_HD=4
 304
 305# The drives for which to adjust the idle timeout. Separate them by a space,
 306# e.g. HD="/dev/hda /dev/hdb".
 307#HD="/dev/hda"
 308
 309# Set the spindown timeout on a hard drive?
 310#DO_HD=1
 311
 312--------------------CONFIG FILE END---------------------------------------------
 313
 314
 315Control script
 316--------------
 317
 318Please note that this control script works for the Linux 2.4 and 2.6 series (thanks
 319to Kiko Piris).
 320
 321--------------------CONTROL SCRIPT BEGIN----------------------------------------
 322#!/bin/bash
 323
 324# start or stop laptop_mode, best run by a power management daemon when
 325# ac gets connected/disconnected from a laptop
 326#
 327# install as /sbin/laptop_mode
 328#
 329# Contributors to this script:   Kiko Piris
 330#                                Bart Samwel
 331#                                Micha Feigin
 332#                                Andrew Morton
 333#                                Herve Eychenne
 334#                                Dax Kelson
 335#
 336# Original Linux 2.4 version by: Jens Axboe
 337
 338#############################################################################
 339
 340# Source config
 341if [ -f /etc/default/laptop-mode ] ; then
 342        # Debian
 343        . /etc/default/laptop-mode
 344elif [ -f /etc/sysconfig/laptop-mode ] ; then
 345        # Others
 346        . /etc/sysconfig/laptop-mode
 347fi
 348
 349# Don't raise an error if the config file is incomplete
 350# set defaults instead:
 351
 352# Maximum time, in seconds, of hard drive spindown time that you are
 353# comfortable with. Worst case, it's possible that you could lose this
 354# amount of work if your battery fails you while in laptop mode.
 355MAX_AGE=${MAX_AGE:-'600'}
 356
 357# Read-ahead, in kilobytes
 358READAHEAD=${READAHEAD:-'4096'}
 359
 360# Shall we remount journaled fs. with appropriate commit interval? (1=yes)
 361DO_REMOUNTS=${DO_REMOUNTS:-'1'}
 362
 363# And shall we add the "noatime" option to that as well? (1=yes)
 364DO_REMOUNT_NOATIME=${DO_REMOUNT_NOATIME:-'1'}
 365
 366# Shall we adjust the idle timeout on a hard drive?
 367DO_HD=${DO_HD:-'1'}
 368
 369# Adjust idle timeout on which hard drive?
 370HD="${HD:-'/dev/hda'}"
 371
 372# spindown time for HD (hdparm -S values)
 373AC_HD=${AC_HD:-'244'}
 374BATT_HD=${BATT_HD:-'4'}
 375
 376# Dirty synchronous ratio.  At this percentage of dirty pages the process which
 377# calls write() does its own writeback
 378DIRTY_RATIO=${DIRTY_RATIO:-'40'}
 379
 380# cpu frequency scaling
 381# See Documentation/cpu-freq/user-guide.txt for more info
 382DO_CPU=${CPU_MANAGE:-'0'}
 383CPU_MAXFREQ=${CPU_MAXFREQ:-'slowest'}
 384
 385#
 386# Allowed dirty background ratio, in percent.  Once DIRTY_RATIO has been
 387# exceeded, the kernel will wake flusher threads which will then reduce the
 388# amount of dirty memory to dirty_background_ratio.  Set this nice and low,
 389# so once some writeout has commenced, we do a lot of it.
 390#
 391DIRTY_BACKGROUND_RATIO=${DIRTY_BACKGROUND_RATIO:-'5'}
 392
 393# kernel default dirty buffer age
 394DEF_AGE=${DEF_AGE:-'30'}
 395DEF_UPDATE=${DEF_UPDATE:-'5'}
 396DEF_DIRTY_BACKGROUND_RATIO=${DEF_DIRTY_BACKGROUND_RATIO:-'10'}
 397DEF_DIRTY_RATIO=${DEF_DIRTY_RATIO:-'40'}
 398DEF_XFS_AGE_BUFFER=${DEF_XFS_AGE_BUFFER:-'15'}
 399DEF_XFS_SYNC_INTERVAL=${DEF_XFS_SYNC_INTERVAL:-'30'}
 400DEF_XFS_BUFD_INTERVAL=${DEF_XFS_BUFD_INTERVAL:-'1'}
 401
 402# This must be adjusted manually to the value of HZ in the running kernel
 403# on 2.4, until the XFS people change their 2.4 external interfaces to work in
 404# centisecs. This can be automated, but it's a work in progress that still needs
 405# some fixes. On 2.6 kernels, XFS uses USER_HZ instead of HZ for external
 406# interfaces, and that is currently always set to 100. So you don't need to
 407# change this on 2.6.
 408XFS_HZ=${XFS_HZ:-'100'}
 409
 410#############################################################################
 411
 412KLEVEL="$(uname -r |
 413             {
 414               IFS='.' read a b c
 415               echo $a.$b
 416             }
 417)"
 418case "$KLEVEL" in
 419        "2.4"|"2.6")
 420                ;;
 421        *)
 422                echo "Unhandled kernel version: $KLEVEL ('uname -r' = '$(uname -r)')" >&2
 423                exit 1
 424                ;;
 425esac
 426
 427if [ ! -e /proc/sys/vm/laptop_mode ] ; then
 428        echo "Kernel is not patched with laptop_mode patch." >&2
 429        exit 1
 430fi
 431
 432if [ ! -w /proc/sys/vm/laptop_mode ] ; then
 433        echo "You do not have enough privileges to enable laptop_mode." >&2
 434        exit 1
 435fi
 436
 437# Remove an option (the first parameter) of the form option=<number> from
 438# a mount options string (the rest of the parameters).
 439parse_mount_opts () {
 440        OPT="$1"
 441        shift
 442        echo ",$*," | sed               \
 443         -e 's/,'"$OPT"'=[0-9]*,/,/g'   \
 444         -e 's/,,*/,/g'                 \
 445         -e 's/^,//'                    \
 446         -e 's/,$//'
 447}
 448
 449# Remove an option (the first parameter) without any arguments from
 450# a mount option string (the rest of the parameters).
 451parse_nonumber_mount_opts () {
 452        OPT="$1"
 453        shift
 454        echo ",$*," | sed               \
 455         -e 's/,'"$OPT"',/,/g'          \
 456         -e 's/,,*/,/g'                 \
 457         -e 's/^,//'                    \
 458         -e 's/,$//'
 459}
 460
 461# Find out the state of a yes/no option (e.g. "atime"/"noatime") in
 462# fstab for a given filesystem, and use this state to replace the
 463# value of the option in another mount options string. The device
 464# is the first argument, the option name the second, and the default
 465# value the third. The remainder is the mount options string.
 466#
 467# Example:
 468# parse_yesno_opts_wfstab /dev/hda1 atime atime defaults,noatime
 469#
 470# If fstab contains, say, "rw" for this filesystem, then the result
 471# will be "defaults,atime".
 472parse_yesno_opts_wfstab () {
 473        L_DEV="$1"
 474        OPT="$2"
 475        DEF_OPT="$3"
 476        shift 3
 477        L_OPTS="$*"
 478        PARSEDOPTS1="$(parse_nonumber_mount_opts $OPT $L_OPTS)"
 479        PARSEDOPTS1="$(parse_nonumber_mount_opts no$OPT $PARSEDOPTS1)"
 480        # Watch for a default atime in fstab
 481        FSTAB_OPTS="$(awk '$1 == "'$L_DEV'" { print $4 }' /etc/fstab)"
 482        if echo "$FSTAB_OPTS" | grep "$OPT" > /dev/null ; then
 483                # option specified in fstab: extract the value and use it
 484                if echo "$FSTAB_OPTS" | grep "no$OPT" > /dev/null ; then
 485                        echo "$PARSEDOPTS1,no$OPT"
 486                else
 487                        # no$OPT not found -- so we must have $OPT.
 488                        echo "$PARSEDOPTS1,$OPT"
 489                fi
 490        else
 491                # option not specified in fstab -- choose the default.
 492                echo "$PARSEDOPTS1,$DEF_OPT"
 493        fi
 494}
 495
 496# Find out the state of a numbered option (e.g. "commit=NNN") in
 497# fstab for a given filesystem, and use this state to replace the
 498# value of the option in another mount options string. The device
 499# is the first argument, and the option name the second. The
 500# remainder is the mount options string in which the replacement
 501# must be done.
 502#
 503# Example:
 504# parse_mount_opts_wfstab /dev/hda1 commit defaults,commit=7
 505#
 506# If fstab contains, say, "commit=3,rw" for this filesystem, then the
 507# result will be "rw,commit=3".
 508parse_mount_opts_wfstab () {
 509        L_DEV="$1"
 510        OPT="$2"
 511        shift 2
 512        L_OPTS="$*"
 513        PARSEDOPTS1="$(parse_mount_opts $OPT $L_OPTS)"
 514        # Watch for a default commit in fstab
 515        FSTAB_OPTS="$(awk '$1 == "'$L_DEV'" { print $4 }' /etc/fstab)"
 516        if echo "$FSTAB_OPTS" | grep "$OPT=" > /dev/null ; then
 517                # option specified in fstab: extract the value, and use it
 518                echo -n "$PARSEDOPTS1,$OPT="
 519                echo ",$FSTAB_OPTS," | sed \
 520                 -e 's/.*,'"$OPT"'=//'  \
 521                 -e 's/,.*//'
 522        else
 523                # option not specified in fstab: set it to 0
 524                echo "$PARSEDOPTS1,$OPT=0"
 525        fi
 526}
 527
 528deduce_fstype () {
 529        MP="$1"
 530        # My root filesystem unfortunately has
 531        # type "unknown" in /etc/mtab. If we encounter
 532        # "unknown", we try to get the type from fstab.
 533        cat /etc/fstab |
 534        grep -v '^#' |
 535        while read FSTAB_DEV FSTAB_MP FSTAB_FST FSTAB_OPTS FSTAB_DUMP FSTAB_DUMP ; do
 536                if [ "$FSTAB_MP" = "$MP" ]; then
 537                        echo $FSTAB_FST
 538                        exit 0
 539                fi
 540        done
 541}
 542
 543if [ $DO_REMOUNT_NOATIME -eq 1 ] ; then
 544        NOATIME_OPT=",noatime"
 545fi
 546
 547case "$1" in
 548        start)
 549                AGE=$((100*$MAX_AGE))
 550                XFS_AGE=$(($XFS_HZ*$MAX_AGE))
 551                echo -n "Starting laptop_mode"
 552
 553                if [ -d /proc/sys/vm/pagebuf ] ; then
 554                        # (For 2.4 and early 2.6.)
 555                        # This only needs to be set, not reset -- it is only used when
 556                        # laptop mode is enabled.
 557                        echo $XFS_AGE > /proc/sys/vm/pagebuf/lm_flush_age
 558                        echo $XFS_AGE > /proc/sys/fs/xfs/lm_sync_interval
 559                elif [ -f /proc/sys/fs/xfs/lm_age_buffer ] ; then
 560                        # (A couple of early 2.6 laptop mode patches had these.)
 561                        # The same goes for these.
 562                        echo $XFS_AGE > /proc/sys/fs/xfs/lm_age_buffer
 563                        echo $XFS_AGE > /proc/sys/fs/xfs/lm_sync_interval
 564                elif [ -f /proc/sys/fs/xfs/age_buffer ] ; then
 565                        # (2.6.6)
 566                        # But not for these -- they are also used in normal
 567                        # operation.
 568                        echo $XFS_AGE > /proc/sys/fs/xfs/age_buffer
 569                        echo $XFS_AGE > /proc/sys/fs/xfs/sync_interval
 570                elif [ -f /proc/sys/fs/xfs/age_buffer_centisecs ] ; then
 571                        # (2.6.7 upwards)
 572                        # And not for these either. These are in centisecs,
 573                        # not USER_HZ, so we have to use $AGE, not $XFS_AGE.
 574                        echo $AGE > /proc/sys/fs/xfs/age_buffer_centisecs
 575                        echo $AGE > /proc/sys/fs/xfs/xfssyncd_centisecs
 576                        echo 3000 > /proc/sys/fs/xfs/xfsbufd_centisecs
 577                fi
 578
 579                case "$KLEVEL" in
 580                        "2.4")
 581                                echo 1                                  > /proc/sys/vm/laptop_mode
 582                                echo "30 500 0 0 $AGE $AGE 60 20 0"     > /proc/sys/vm/bdflush
 583                                ;;
 584                        "2.6")
 585                                echo 5                                  > /proc/sys/vm/laptop_mode
 586                                echo "$AGE"                             > /proc/sys/vm/dirty_writeback_centisecs
 587                                echo "$AGE"                             > /proc/sys/vm/dirty_expire_centisecs
 588                                echo "$DIRTY_RATIO"                     > /proc/sys/vm/dirty_ratio
 589                                echo "$DIRTY_BACKGROUND_RATIO"          > /proc/sys/vm/dirty_background_ratio
 590                                ;;
 591                esac
 592                if [ $DO_REMOUNTS -eq 1 ]; then
 593                        cat /etc/mtab | while read DEV MP FST OPTS DUMP PASS ; do
 594                                PARSEDOPTS="$(parse_mount_opts "$OPTS")"
 595                                if [ "$FST" = 'unknown' ]; then
 596                                        FST=$(deduce_fstype $MP)
 597                                fi
 598                                case "$FST" in
 599                                        "ext3"|"reiserfs")
 600                                                PARSEDOPTS="$(parse_mount_opts commit "$OPTS")"
 601                                                mount $DEV -t $FST $MP -o remount,$PARSEDOPTS,commit=$MAX_AGE$NOATIME_OPT
 602                                                ;;
 603                                        "xfs")
 604                                                mount $DEV -t $FST $MP -o remount,$OPTS$NOATIME_OPT
 605                                                ;;
 606                                esac
 607                                if [ -b $DEV ] ; then
 608                                        blockdev --setra $(($READAHEAD * 2)) $DEV
 609                                fi
 610                        done
 611                fi
 612                if [ $DO_HD -eq 1 ] ; then
 613                        for THISHD in $HD ; do
 614                                /sbin/hdparm -S $BATT_HD $THISHD > /dev/null 2>&1
 615                                /sbin/hdparm -B 1 $THISHD > /dev/null 2>&1
 616                        done
 617                fi
 618                if [ $DO_CPU -eq 1 -a -e /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq ]; then
 619                        if [ $CPU_MAXFREQ = 'slowest' ]; then
 620                                CPU_MAXFREQ=`cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq`
 621                        fi
 622                        echo $CPU_MAXFREQ > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
 623                fi
 624                echo "."
 625                ;;
 626        stop)
 627                U_AGE=$((100*$DEF_UPDATE))
 628                B_AGE=$((100*$DEF_AGE))
 629                echo -n "Stopping laptop_mode"
 630                echo 0 > /proc/sys/vm/laptop_mode
 631                if [ -f /proc/sys/fs/xfs/age_buffer -a ! -f /proc/sys/fs/xfs/lm_age_buffer ] ; then
 632                        # These need to be restored, if there are no lm_*.
 633                        echo $(($XFS_HZ*$DEF_XFS_AGE_BUFFER))           > /proc/sys/fs/xfs/age_buffer
 634                        echo $(($XFS_HZ*$DEF_XFS_SYNC_INTERVAL))        > /proc/sys/fs/xfs/sync_interval
 635                elif [ -f /proc/sys/fs/xfs/age_buffer_centisecs ] ; then
 636                        # These need to be restored as well.
 637                        echo $((100*$DEF_XFS_AGE_BUFFER))       > /proc/sys/fs/xfs/age_buffer_centisecs
 638                        echo $((100*$DEF_XFS_SYNC_INTERVAL))    > /proc/sys/fs/xfs/xfssyncd_centisecs
 639                        echo $((100*$DEF_XFS_BUFD_INTERVAL))    > /proc/sys/fs/xfs/xfsbufd_centisecs
 640                fi
 641                case "$KLEVEL" in
 642                        "2.4")
 643                                echo "30 500 0 0 $U_AGE $B_AGE 60 20 0" > /proc/sys/vm/bdflush
 644                                ;;
 645                        "2.6")
 646                                echo "$U_AGE"                           > /proc/sys/vm/dirty_writeback_centisecs
 647                                echo "$B_AGE"                           > /proc/sys/vm/dirty_expire_centisecs
 648                                echo "$DEF_DIRTY_RATIO"                 > /proc/sys/vm/dirty_ratio
 649                                echo "$DEF_DIRTY_BACKGROUND_RATIO"      > /proc/sys/vm/dirty_background_ratio
 650                                ;;
 651                esac
 652                if [ $DO_REMOUNTS -eq 1 ] ; then
 653                        cat /etc/mtab | while read DEV MP FST OPTS DUMP PASS ; do
 654                                # Reset commit and atime options to defaults.
 655                                if [ "$FST" = 'unknown' ]; then
 656                                        FST=$(deduce_fstype $MP)
 657                                fi
 658                                case "$FST" in
 659                                        "ext3"|"reiserfs")
 660                                                PARSEDOPTS="$(parse_mount_opts_wfstab $DEV commit $OPTS)"
 661                                                PARSEDOPTS="$(parse_yesno_opts_wfstab $DEV atime atime $PARSEDOPTS)"
 662                                                mount $DEV -t $FST $MP -o remount,$PARSEDOPTS
 663                                                ;;
 664                                        "xfs")
 665                                                PARSEDOPTS="$(parse_yesno_opts_wfstab $DEV atime atime $OPTS)"
 666                                                mount $DEV -t $FST $MP -o remount,$PARSEDOPTS
 667                                                ;;
 668                                esac
 669                                if [ -b $DEV ] ; then
 670                                        blockdev --setra 256 $DEV
 671                                fi
 672                        done
 673                fi
 674                if [ $DO_HD -eq 1 ] ; then
 675                        for THISHD in $HD ; do
 676                                /sbin/hdparm -S $AC_HD $THISHD > /dev/null 2>&1
 677                                /sbin/hdparm -B 255 $THISHD > /dev/null 2>&1
 678                        done
 679                fi
 680                if [ $DO_CPU -eq 1 -a -e /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq ]; then
 681                        echo `cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq` > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
 682                fi
 683                echo "."
 684                ;;
 685        *)
 686                echo "Usage: $0 {start|stop}" 2>&1
 687                exit 1
 688                ;;
 689
 690esac
 691
 692exit 0
 693--------------------CONTROL SCRIPT END------------------------------------------
 694
 695
 696ACPI integration
 697----------------
 698
 699Dax Kelson submitted this so that the ACPI acpid daemon will
 700kick off the laptop_mode script and run hdparm. The part that
 701automatically disables laptop mode when the battery is low was
 702written by Jan Topinski.
 703
 704-----------------/etc/acpi/events/ac_adapter BEGIN------------------------------
 705event=ac_adapter
 706action=/etc/acpi/actions/ac.sh %e
 707----------------/etc/acpi/events/ac_adapter END---------------------------------
 708
 709
 710-----------------/etc/acpi/events/battery BEGIN---------------------------------
 711event=battery.*
 712action=/etc/acpi/actions/battery.sh %e
 713----------------/etc/acpi/events/battery END------------------------------------
 714
 715
 716----------------/etc/acpi/actions/ac.sh BEGIN-----------------------------------
 717#!/bin/bash
 718
 719# ac on/offline event handler
 720
 721status=`awk '/^state: / { print $2 }' /proc/acpi/ac_adapter/$2/state`
 722
 723case $status in
 724        "on-line")
 725                /sbin/laptop_mode stop
 726                exit 0
 727        ;;
 728        "off-line")
 729                /sbin/laptop_mode start
 730                exit 0
 731        ;;
 732esac
 733---------------------------/etc/acpi/actions/ac.sh END--------------------------
 734
 735
 736---------------------------/etc/acpi/actions/battery.sh BEGIN-------------------
 737#! /bin/bash
 738
 739# Automatically disable laptop mode when the battery almost runs out.
 740
 741BATT_INFO=/proc/acpi/battery/$2/state
 742
 743if [[ -f /proc/sys/vm/laptop_mode ]]
 744then
 745   LM=`cat /proc/sys/vm/laptop_mode`
 746   if [[ $LM -gt 0 ]]
 747   then
 748     if [[ -f $BATT_INFO ]]
 749     then
 750        # Source the config file only now that we know we need
 751        if [ -f /etc/default/laptop-mode ] ; then
 752                # Debian
 753                . /etc/default/laptop-mode
 754        elif [ -f /etc/sysconfig/laptop-mode ] ; then
 755                # Others
 756                . /etc/sysconfig/laptop-mode
 757        fi
 758        MINIMUM_BATTERY_MINUTES=${MINIMUM_BATTERY_MINUTES:-'10'}
 759
 760        ACTION="`cat $BATT_INFO | grep charging | cut -c 26-`"
 761        if [[ ACTION -eq "discharging" ]]
 762        then
 763           PRESENT_RATE=`cat $BATT_INFO | grep "present rate:" | sed  "s/.* \([0-9][0-9]* \).*/\1/" `
 764           REMAINING=`cat $BATT_INFO | grep "remaining capacity:" | sed  "s/.* \([0-9][0-9]* \).*/\1/" `
 765        fi
 766        if (($REMAINING * 60 / $PRESENT_RATE < $MINIMUM_BATTERY_MINUTES))
 767        then
 768           /sbin/laptop_mode stop
 769        fi
 770     else
 771       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."
 772     fi
 773   fi
 774fi
 775---------------------------/etc/acpi/actions/battery.sh END--------------------
 776
 777
 778Monitoring tool
 779---------------
 780
 781Bartek Kania submitted this, it can be used to measure how much time your disk
 782spends spun up/down.  See Documentation/laptops/dslm.c
 783
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