Documentation/laptop-mode.txt

   1 How to conserve battery power using laptop-mode
   2 -----------------------------------------------
   3
   4 Document Author: Bart Samwel (bart@samwel.tk)
   5 Date created: January 2, 2004
   6 Last modified: July 10, 2004
   7
   8 Introduction
   9 ------------
  10
  11 Laptop mode is used to minimize the time that the hard disk needs to be spun up,
  12 to conserve battery power on laptops. It has been reported to cause significant
  13 power savings.
  14
  15 Contents
  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
  28 Installation
  29 ------------
  30
  31 To use laptop mode, you don't need to set any kernel configuration options
  32 or anything. Simply install all the files included in this document, and
  33 laptop mode will automatically be started when you're on battery. For
  34 your convenience, a tarball containing an installer can be downloaded at:
  35
  36 http://www.xs4all.nl/~bsamwel/laptop_mode/tools
  37
  38 To configure laptop mode, you need to edit the configuration file, which is
  39 located in /etc/default/laptop-mode on Debian-based systems, or in
  40 /etc/sysconfig/laptop-mode on other systems.
  41
  42 Unfortunately, automatic enabling of laptop mode does not work for
  43 laptops that don't have ACPI. On those laptops, you need to start laptop
  44 mode manually. To start laptop mode, run "laptop_mode start", and to
  45 stop it, run "laptop_mode stop". (Note: The laptop mode tools package now
  46 has experimental support for APM, you might want to try that first.)
  47
  48
  49 Caveats
  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
  77 The Details
  78 -----------
  79
  80 Laptop mode is controlled by the knob /proc/sys/vm/laptop_mode. This knob is
  81 present for all kernels that have the laptop mode patch, regardless of any
  82 configuration options. When the knob is set, any physical disk I/O (that might
  83 have caused the hard disk to spin up) causes Linux to flush all dirty blocks. The
  84 result of this is that after a disk has spun down, it will not be spun up
  85 anymore to write dirty blocks, because those blocks had already been written
  86 immediately after the most recent read operation. The value of the laptop_mode
  87 knob determines the time between the occurrence of disk I/O and when the flush
  88 is triggered. A sensible value for the knob is 5 seconds. Setting the knob to
  89 0 disables laptop mode.
  90
  91 To increase the effectiveness of the laptop_mode strategy, the laptop_mode
  92 control 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
  94 dirtied are not forced to be written to disk as often. The control script also
  95 changes the dirty background ratio, so that background writeback of dirty pages
  96 is not done anymore. Combined with a higher commit value (also 10 minutes) for
  97 ext3 or ReiserFS filesystems (also done automatically by the control script),
  98 this results in concentration of disk activity in a small time interval which
  99 occurs only once every 10 minutes, or whenever the disk is forced to spin up by
 100 a cache miss. The disk can then be spun down in the periods of inactivity.
 101
 102 If you want to find out which process caused the disk to spin up, you can
 103 gather information by setting the flag /proc/sys/vm/block_dump. When this flag
 104 is set, Linux reports all disk read and write operations that take place, and
 105 all block dirtyings done to files. This makes it possible to debug why a disk
 106 needs to spin up, and to increase battery life even more. The output of
 107 block_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
 109 kernel debugging messages, you probably want to turn off klogd, otherwise
 110 the output of block_dump will be logged, causing disk activity that is not
 111 normally there.
 112
 113
 114 Configuration
 115 -------------
 116
 117 The laptop mode configuration file is located in /etc/default/laptop-mode on
 118 Debian-based systems, or in /etc/sysconfig/laptop-mode on other systems. It
 119 contains the following options:
 120
 121 MAX_AGE:
 122
 123 Maximum time, in seconds, of hard drive spindown time that you are
 124 confortable with. Worst case, it's possible that you could lose this
 125 amount of work if your battery fails while you're in laptop mode.
 126
 127 MINIMUM_BATTERY_MINUTES:
 128
 129 Automatically disable laptop mode if the remaining number of minutes of
 130 battery power is less than this value. Default is 10 minutes.
 131
 132 AC_HD/BATT_HD:
 133
 134 The idle timeout that should be set on your hard drive when laptop mode
 135 is active (BATT_HD) and when it is not active (AC_HD). The defaults are
 136 20 seconds (value 4) for BATT_HD  and 2 hours (value 244) for AC_HD. The
 137 possible values are those listed in the manual page for "hdparm" for the
 138 "-S" option.
 139
 140 HD:
 141
 142 The devices for which the spindown timeout should be adjusted by laptop mode.
 143 Default is /dev/hda. If you specify multiple devices, separate them by a space.
 144
 145 READAHEAD:
 146
 147 Disk readahead, in 512-byte sectors, while laptop mode is active. A large
 148 readahead can prevent disk accesses for things like executable pages (which are
 149 loaded on demand while the application executes) and sequentially accessed data
 150 (MP3s).
 151
 152 DO_REMOUNTS:
 153
 154 The control script automatically remounts any mounted journaled filesystems
 155 with approriate commit interval options. When this option is set to 0, this
 156 feature is disabled.
 157
 158 DO_REMOUNT_NOATIME:
 159
 160 When remounting, should the filesystems be remounted with the noatime option?
 161 Normally, this is set to "1" (enabled), but there may be programs that require
 162 access time recording.
 163
 164 DIRTY_RATIO:
 165
 166 The percentage of memory that is allowed to contain "dirty" or unsaved data
 167 before a writeback is forced, while laptop mode is active. Corresponds to
 168 the /proc/sys/vm/dirty_ratio sysctl.
 169
 170 DIRTY_BACKGROUND_RATIO:
 171
 172 The percentage of memory that is allowed to contain "dirty" or unsaved data
 173 after a forced writeback is done due to an exceeding of DIRTY_RATIO. Set
 174 this nice and low. This corresponds to the /proc/sys/vm/dirty_background_ratio
 175 sysctl.
 176
 177 Note that the behaviour of dirty_background_ratio is quite different
 178 when laptop mode is active and when it isn't. When laptop mode is inactive,
 179 dirty_background_ratio is the threshold percentage at which background writeouts
 180 start taking place. When laptop mode is active, however, background writeouts
 181 are disabled, and the dirty_background_ratio only determines how much writeback
 182 is done when dirty_ratio is reached.
 183
 184 DO_CPU:
 185
 186 Enable CPU frequency scaling when in laptop mode. (Requires CPUFreq to be setup.
 187 See Documentation/cpu-freq/user-guide.txt for more info. Disabled by default.)
 188
 189 CPU_MAXFREQ:
 190
 191 When on battery, what is the maximum CPU speed that the system should use? Legal
 192 values are "slowest" for the slowest speed that your CPU is able to operate at,
 193 or a value listed in /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies.
 194
 195
 196 Tips & 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 it's 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
 227 Configuration file for control and ACPI battery scripts
 228 -------------------------------------------------------
 229
 230 This allows the tunables to be changed for the scripts via an external
 231 configuration file
 232
 233 It 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 # confortable 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.
 244 MINIMUM_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 pdflush which will then reduce the amount
 266 # of dirty memory to dirty_background_ratio.  Set this nice and low, so once
 267 # 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
 315 Control script
 316 --------------
 317
 318 Please note that this control script works for the Linux 2.4 and 2.6 series (thanks
 319 to 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
 341 if [ -f /etc/default/laptop-mode ] ; then
 342         # Debian
 343         . /etc/default/laptop-mode
 344 elif [ -f /etc/sysconfig/laptop-mode ] ; then
 345         # Others
 346         . /etc/sysconfig/laptop-mode
 347 fi
 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 # confortable with. Worst case, it's possible that you could lose this
 354 # amount of work if your battery fails you while in laptop mode.
 355 MAX_AGE=${MAX_AGE:-'600'}
 356
 357 # Read-ahead, in kilobytes
 358 READAHEAD=${READAHEAD:-'4096'}
 359
 360 # Shall we remount journaled fs. with appropiate commit interval? (1=yes)
 361 DO_REMOUNTS=${DO_REMOUNTS:-'1'}
 362
 363 # And shall we add the "noatime" option to that as well? (1=yes)
 364 DO_REMOUNT_NOATIME=${DO_REMOUNT_NOATIME:-'1'}
 365
 366 # Shall we adjust the idle timeout on a hard drive?
 367 DO_HD=${DO_HD:-'1'}
 368
 369 # Adjust idle timeout on which hard drive?
 370 HD="${HD:-'/dev/hda'}"
 371
 372 # spindown time for HD (hdparm -S values)
 373 AC_HD=${AC_HD:-'244'}
 374 BATT_HD=${BATT_HD:-'4'}
 375
 376 # Dirty synchronous ratio.  At this percentage of dirty pages the process which
 377 # calls write() does its own writeback
 378 DIRTY_RATIO=${DIRTY_RATIO:-'40'}
 379
 380 # cpu frequency scaling
 381 # See Documentation/cpu-freq/user-guide.txt for more info
 382 DO_CPU=${CPU_MANAGE:-'0'}
 383 CPU_MAXFREQ=${CPU_MAXFREQ:-'slowest'}
 384
 385 #
 386 # Allowed dirty background ratio, in percent.  Once DIRTY_RATIO has been
 387 # exceeded, the kernel will wake pdflush which will then reduce the amount
 388 # of dirty memory to dirty_background_ratio.  Set this nice and low, so once
 389 # some writeout has commenced, we do a lot of it.
 390 #
 391 DIRTY_BACKGROUND_RATIO=${DIRTY_BACKGROUND_RATIO:-'5'}
 392
 393 # kernel default dirty buffer age
 394 DEF_AGE=${DEF_AGE:-'30'}
 395 DEF_UPDATE=${DEF_UPDATE:-'5'}
 396 DEF_DIRTY_BACKGROUND_RATIO=${DEF_DIRTY_BACKGROUND_RATIO:-'10'}
 397 DEF_DIRTY_RATIO=${DEF_DIRTY_RATIO:-'40'}
 398 DEF_XFS_AGE_BUFFER=${DEF_XFS_AGE_BUFFER:-'15'}
 399 DEF_XFS_SYNC_INTERVAL=${DEF_XFS_SYNC_INTERVAL:-'30'}
 400 DEF_XFS_BUFD_INTERVAL=${DEF_XFS_BUFD_INTERVAL:-'1'}
 401
 402 # This must be adjusted manually to the value of HZ in the running kernel
 403 # on 2.4, until the XFS people change their 2.4 external interfaces to work in
 404 # centisecs. This can be automated, but it's a work in progress that still needs
 405 # some fixes. On 2.6 kernels, XFS uses USER_HZ instead of HZ for external
 406 # interfaces, and that is currently always set to 100. So you don't need to
 407 # change this on 2.6.
 408 XFS_HZ=${XFS_HZ:-'100'}
 409
 410 #############################################################################
 411
 412 KLEVEL="$(uname -r |
 413              {
 414                IFS='.' read a b c
 415                echo $a.$b
 416              }
 417 )"
 418 case "$KLEVEL" in
 419         "2.4"|"2.6")
 420                 ;;
 421         *)
 422                 echo "Unhandled kernel version: $KLEVEL ('uname -r' = '$(uname -r)')" >&2
 423                 exit 1
 424                 ;;
 425 esac
 426
 427 if [ ! -e /proc/sys/vm/laptop_mode ] ; then
 428         echo "Kernel is not patched with laptop_mode patch." >&2
 429         exit 1
 430 fi
 431
 432 if [ ! -w /proc/sys/vm/laptop_mode ] ; then
 433         echo "You do not have enough privileges to enable laptop_mode." >&2
 434         exit 1
 435 fi
 436
 437 # Remove an option (the first parameter) of the form option=<number> from
 438 # a mount options string (the rest of the parameters).
 439 parse_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).
 451 parse_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".
 472 parse_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".
 508 parse_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
 528 deduce_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
 543 if [ $DO_REMOUNT_NOATIME -eq 1 ] ; then
 544         NOATIME_OPT=",noatime"
 545 fi
 546
 547 case "$1" in
 548         start)
 549                 AGE=$((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
 690 esac
 691
 692 exit 0
 693 --------------------CONTROL SCRIPT END------------------------------------------
 694
 695
 696 ACPI integration
 697 ----------------
 698
 699 Dax Kelson submitted this so that the ACPI acpid daemon will
 700 kick off the laptop_mode script and run hdparm. The part that
 701 automatically disables laptop mode when the battery is low was
 702 writen by Jan Topinski.
 703
 704 -----------------/etc/acpi/events/ac_adapter BEGIN------------------------------
 705 event=ac_adapter
 706 action=/etc/acpi/actions/ac.sh %e
 707 ----------------/etc/acpi/events/ac_adapter END---------------------------------
 708
 709
 710 -----------------/etc/acpi/events/battery BEGIN---------------------------------
 711 event=battery.*
 712 action=/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
 721 status=`awk '/^state: / { print $2 }' /proc/acpi/ac_adapter/$2/state`
 722
 723 case $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         ;;
 732 esac
 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
 741 BATT_INFO=/proc/acpi/battery/$2/state
 742
 743 if [[ -f /proc/sys/vm/laptop_mode ]]
 744 then
 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
 774 fi
 775 ---------------------------/etc/acpi/actions/battery.sh END--------------------
 776
 777
 778 Monitoring tool
 779 ---------------
 780
 781 Bartek Kania submitted this, it can be used to measure how much time your disk
 782 spends spun up/down.
 783
 784 ---------------------------dslm.c BEGIN-----------------------------------------
 785 /*
 786  * Simple Disk Sleep Monitor
 787  *  by Bartek Kania
 788  * Licenced under the GPL
 789  */
 790 #include <unistd.h>
 791 #include <stdlib.h>
 792 #include <stdio.h>
 793 #include <fcntl.h>
 794 #include <errno.h>
 795 #include <time.h>
 796 #include <string.h>
 797 #include <signal.h>
 798 #include <sys/ioctl.h>
 799 #include <linux/hdreg.h>
 800
 801 #ifdef DEBUG
 802 #define D(x) x
 803 #else
 804 #define D(x)
 805 #endif
 806
 807 int endit = 0;
 808
 809 /* Check if the disk is in powersave-mode
 810  * Most of the code is stolen from hdparm.
 811  * 1 = active, 0 = standby/sleep, -1 = unknown */
 812 int check_powermode(int fd)
 813 {
 814     unsigned char args[4] = {WIN_CHECKPOWERMODE1,0,0,0};
 815     int state;
 816
 817     if (ioctl(fd, HDIO_DRIVE_CMD, &args)
 818         && (args[0] = WIN_CHECKPOWERMODE2) /* try again with 0x98 */
 819         && ioctl(fd, HDIO_DRIVE_CMD, &args)) {
 820         if (errno != EIO || args[0] != 0 || args[1] != 0) {
 821             state = -1; /* "unknown"; */
 822         } else
 823             state = 0; /* "sleeping"; */
 824     } else {
 825         state = (args[2] == 255) ? 1 : 0;
 826     }
 827     D(printf(" drive state is:  %d\n", state));
 828
 829     return state;
 830 }
 831
 832 char *state_name(int i)
 833 {
 834     if (i == -1) return "unknown";
 835     if (i == 0) return "sleeping";
 836     if (i == 1) return "active";
 837
 838     return "internal error";
 839 }
 840
 841 char *myctime(time_t time)
 842 {
 843     char *ts = ctime(&time);
 844     ts[strlen(ts) - 1] = 0;
 845
 846     return ts;
 847 }
 848
 849 void measure(int fd)
 850 {
 851     time_t start_time;
 852     int last_state;
 853     time_t last_time;
 854     int curr_state;
 855     time_t curr_time = 0;
 856     time_t time_diff;
 857     time_t active_time = 0;
 858     time_t sleep_time = 0;
 859     time_t unknown_time = 0;
 860     time_t total_time = 0;
 861     int changes = 0;
 862     float tmp;
 863
 864     printf("Starting measurements\n");
 865
 866     last_state = check_powermode(fd);
 867     start_time = last_time = time(0);
 868     printf("  System is in state %s\n\n", state_name(last_state));
 869
 870     while(!endit) {
 871         sleep(1);
 872         curr_state = check_powermode(fd);
 873
 874         if (curr_state != last_state || endit) {
 875             changes++;
 876             curr_time = time(0);
 877             time_diff = curr_time - last_time;
 878
 879             if (last_state == 1) active_time += time_diff;
 880             else if (last_state == 0) sleep_time += time_diff;
 881             else unknown_time += time_diff;
 882
 883             last_state = curr_state;
 884             last_time = curr_time;
 885
 886             printf("%s: State-change to %s\n", myctime(curr_time),
 887                    state_name(curr_state));
 888         }
 889     }
 890     changes--; /* Compensate for SIGINT */
 891
 892     total_time = time(0) - start_time;
 893     printf("\nTotal running time:  %lus\n", curr_time - start_time);
 894     printf(" State changed %d times\n", changes);
 895
 896     tmp = (float)sleep_time / (float)total_time * 100;
 897     printf(" Time in sleep state:   %lus (%.2f%%)\n", sleep_time, tmp);
 898     tmp = (float)active_time / (float)total_time * 100;
 899     printf(" Time in active state:  %lus (%.2f%%)\n", active_time, tmp);
 900     tmp = (float)unknown_time / (float)total_time * 100;
 901     printf(" Time in unknown state: %lus (%.2f%%)\n", unknown_time, tmp);
 902 }
 903
 904 void ender(int s)
 905 {
 906     endit = 1;
 907 }
 908
 909 void usage()
 910 {
 911     puts("usage: dslm [-w <time>] <disk>");
 912     exit(0);
 913 }
 914
 915 int main(int ac, char **av)
 916 {
 917     int fd;
 918     char *disk = 0;
 919     int settle_time = 60;
 920
 921     /* Parse the simple command-line */
 922     if (ac == 2)
 923         disk = av[1];
 924     else if (ac == 4) {
 925         settle_time = atoi(av[2]);
 926         disk = av[3];
 927     } else
 928         usage();
 929
 930     if (!(fd = open(disk, O_RDONLY|O_NONBLOCK))) {
 931         printf("Can't open %s, because: %s\n", disk, strerror(errno));
 932         exit(-1);
 933     }
 934
 935     if (settle_time) {
 936         printf("Waiting %d seconds for the system to settle down to "
 937                "'normal'\n", settle_time);
 938         sleep(settle_time);
 939     } else
 940         puts("Not waiting for system to settle down");
 941
 942     signal(SIGINT, ender);
 943
 944     measure(fd);
 945
 946     close(fd);
 947
 948     return 0;
 949 }
 950 ---------------------------dslm.c END-------------------------------------------