ahoffmann
asked on
bdflush (monitoring activity)
to keep my Laptop silent I'm using following
echo "90 2000 0 0 360000 360000 90 0 0" > /proc/sys/vm/bdflush
/sbin/hdparm -S 12 /dev/hda
/sbin/hdparm -y /dev/hda
(don't worry about the values for bdflush, they are not perfect, I know:)
this works perfect for my 2.4 kernel (all versions up to 2.4.25 now) silence most the time !
But sometimes the system (kernel, whatever) continues to makes disk-access all the time for unknown reason.
Most likely this happens after wake-up from suspend to RAM (I never switch off Linux:).
Once in the state where disk-access is frequently, I need to echo to /proc/...bdflush again.
Sometimes it behaves as expected: silence, sometimes not.
1. How can I identify what caused the disk-access? Is there some debugging functionality?
Note that I switched off most daemons (cron, at, etc.), or have tuned them (syslogd).
There're no processes which require disk (swap).
Also running sync does not help. /sbin/hdparm -y /dev/hda again with no avail too.
The kernel docs describing /proc/sys/vm/bdflush are not very helpfull.
echo "90 2000 0 0 360000 360000 90 0 0" > /proc/sys/vm/bdflush
/sbin/hdparm -S 12 /dev/hda
/sbin/hdparm -y /dev/hda
(don't worry about the values for bdflush, they are not perfect, I know:)
this works perfect for my 2.4 kernel (all versions up to 2.4.25 now) silence most the time !
But sometimes the system (kernel, whatever) continues to makes disk-access all the time for unknown reason.
Most likely this happens after wake-up from suspend to RAM (I never switch off Linux:).
Once in the state where disk-access is frequently, I need to echo to /proc/...bdflush again.
Sometimes it behaves as expected: silence, sometimes not.
1. How can I identify what caused the disk-access? Is there some debugging functionality?
Note that I switched off most daemons (cron, at, etc.), or have tuned them (syslogd).
There're no processes which require disk (swap).
Also running sync does not help. /sbin/hdparm -y /dev/hda again with no avail too.
The kernel docs describing /proc/sys/vm/bdflush are not very helpfull.
ASKER
Thanks, I'll check but it needs a reboot, so takes a while ....
I'm sure you'll get a lot from ltt Achim... But you can egt a surprising amount of info from such a simple tool as a modern top. Just choose/sort by fields that should indicate any "suspicious" activity:-).
-- Glenn
-- Glenn
ASKER
top?
which field does tell anything about disk access? Think vmstat is more useful here ('til Linux releases prstat:)
which field does tell anything about disk access? Think vmstat is more useful here ('til Linux releases prstat:)
None!
But you could "build a case" against some likely suspect.
Unfortunately vmstat/iostat/sar give rather little correlation to each process... Which ultimately must be your goal to identify(?)... So top/ps/trawling proc it is then. And these give next to no correlation to actual IO.
And modern day top gives a bit more info than it used to, wouldn't you say? So ... just a friendly reminder that the "lowbudget tools of everyday" actually can be of use.
"Lack of correlation" is of course rather expected with buffered IO and all:-).
-- Glenn
But you could "build a case" against some likely suspect.
Unfortunately vmstat/iostat/sar give rather little correlation to each process... Which ultimately must be your goal to identify(?)... So top/ps/trawling proc it is then. And these give next to no correlation to actual IO.
And modern day top gives a bit more info than it used to, wouldn't you say? So ... just a friendly reminder that the "lowbudget tools of everyday" actually can be of use.
"Lack of correlation" is of course rather expected with buffered IO and all:-).
-- Glenn
for kernel 2.6
you can try this
# sysctl -w vm.swappiness=20
# echo 20 >/proc/sys/vm/swappiness
# Control how much the kernel should favor swapping out applications (0-100)
vm.swappiness = 20
20 is good for laptops
you can try this
# sysctl -w vm.swappiness=20
# echo 20 >/proc/sys/vm/swappiness
# Control how much the kernel should favor swapping out applications (0-100)
vm.swappiness = 20
20 is good for laptops
ASKER
I don't have 2.6 for now, and my feeling is that it is not a swap-problem, 'cause "something" starts to use the disk continously, sometimes ... (see my question: Most likely this happens after wake-up ...)
Hm, you're sure you "kill off" all the "magic dev/supermount" type things?
-- Glenn
-- Glenn
ASKER
what do you mean Glenn?
You know, the "autoplay" type of stuff litterling most any distro and desktop...:-). Mdk have the abominable supermount kernel module for it, Gnome has the "magicdev daemon" etc...
Something like that might just go slightly bonkers from time to time, especially after a suspend/wakeup.
Just a thought.
-- Glenn
Something like that might just go slightly bonkers from time to time, especially after a suspend/wakeup.
Just a thought.
-- Glenn
ASKER
my laptop is a working mashine not a multi-media center, LAN, keyborad and ASCII-screen nothing else ;-)
does this answer your suggestion, Glenn?
does this answer your suggestion, Glenn?
Almost forgot who I was talking to.... Should've known better than to ask such silly things:-).
-- Glenn
-- Glenn
No comment has been added to this question in more than 21 days, so it is now classified as abandoned..
I will leave the following recommendation for this question in the Cleanup topic area:
PAQ-Refund
Any objections should be posted here in the next 4 days. After that time, the question will be closed.
Knollbert
EE Cleanup Volunteer
I will leave the following recommendation for this question in the Cleanup topic area:
PAQ-Refund
Any objections should be posted here in the next 4 days. After that time, the question will be closed.
Knollbert
EE Cleanup Volunteer
ASKER
didn't find a valuable solution yet, and no time to dig deep into kernel debugging ...
Anybody agrees that we PAQ this question with 0 points:
I'll post a dummy question for dbacalja 'cause http:#11240967 seems the way to go
Anybody agrees that we PAQ this question with 0 points:
I'll post a dummy question for dbacalja 'cause http:#11240967 seems the way to go
No objections.
-- Glenn
-- Glenn
ASKER CERTIFIED SOLUTION
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ASKER
dbacalja please see https://www.experts-exchange.com/questions/21154164/Points-for-dbacalja.html
did you mount all your filesystems with the "noatime" option ?
Read an article about it here (has an example):
http://www.linuxjournal.com/article.php?sid=3829
You can get the toolkit from here:
http://www.opersys.com/LTT/