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