linux-kernel - Re: Re: reiserfs do_journal

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Message-ID: <1df1788c0809041632h726fff6cq2eacd86076215017@mail.gmail.com>
Date:	Thu, 4 Sep 2008 20:32:37 -0300
From:	"Bráulio Barros de Oliveira" <brauliobo@...il.com>
To:	Mat <jackdachef@...il.com>
Cc:	reiserfs-devel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: Re: reiserfs do_journal_end unnecessary hd wake up?

but (as always there is), the situation is not good yet when using kde4.
with it, i can't find out which process is accessing the hd, cause
iotop only shows a pdflush access.
i've tried to kill some apps, but it didn't help. any other trace technic?

regards,
bráulio

On Thu, Sep 4, 2008 at 8:28 PM, Bráulio Barros de Oliveira
<brauliobo@...il.com> wrote:
> hello mat, here comes the results of each action.
> in all the process i've used the iotop (what a great utility you
> pointed!), and always saw only the pdflush process acessing the hd. no
> user interface were used.
> the apm is set to 128 with hdparm
>
> ok, then try the following:
>
> you at least should have noatime,nodiratime,commit=600
>
> :) that did the job! also, i've tested without the commit option,
> which didn't changed the result.
>
> enabled for the reiserfs or >=ext3 filesystems
>
> you can also try data=writeback (but beware this might put your data at risk !)
>
> * can't try
>
> select the anticipatory i/o scheduler
> and set following stuff
>
> :( no change.
>
> echo "16" > /proc/sys/vm/page-cluster
> # default: 3
> #
>
> :( no change.
>
> echo "60" > /proc/sys/vm/swappiness
> # default: 60
> # By default, Linux will aggressively swap processes out of physical memory onto
> disk in order to keep the disk cache as large as possible.
> # This means that pages that haven't been used recently will be pushed into swap
> long before the system even comes close to running out of memory, which is an
> unexpected behavior compared to some operating systems.
> # The /proc/sys/vm/swappiness parameter controls how aggressive Linux is in this
> area.
>
> :( no change.
>
> echo "3000" > /proc/sys/vm/dirty_expire_centisecs
> # default: 3000 (30 seconds)
> #2 how long data can be in the page cache before it is considered expired and
> must be written at the next opportunity. Note that this default is very long: a
> full 30 seconds. That means that under normal circumstances, unless you write
> enough to trigger the other pdflush method, Linux won't actually commit anything
> you write until 30 seconds later.
>
> :( no change.
>
> echo "6000"  > /proc/sys/vm/dirty_writeback_centisecs
> # default: 500 (5 seconds)
> #1 how often pdflush wakes up to write data to disk. The default wakes up the
> two (or more) active threads every five seconds.
> # suggestion: 6000 (every 60 seconds)
>
> :( no change.
>
> echo "15" > /proc/sys/vm/dirty_background_ratio
> # default: 10
> #3 Maximum percentage of active memory that can be filled with dirty pages
> before pdflush begins to write them
>
> echo "50"   > /proc/sys/vm/dirty_ratio #modified
> # default: 40
> #4 Maximum percentage of total memory that can be filled with dirty pages before
> processes are forced to write dirty buffers themselves during their time slice
> instead of being allowed to do more writes.
> # modified: 50
>
> echo "25" > /proc/sys/vm/vfs_cache_pressure
>
> for i in /sys/block/sd*; do
>        /bin/echo "anticipatory" >  $i/queue/scheduler
> done
>
> for i in /sys/block/sd*; do
>        /bin/echo "0" >  $i/queue/iosched/antic_expire
> done
>
> for i in /sys/block/sd*; do
>        /bin/echo "150" >  $i/queue/iosched/read_expire
> done
>
> for i in /sys/block/sd*; do
>        /bin/echo "750" >  $i/queue/iosched/read_batch_expire
> done
>
> for i in /sys/block/sd*; do
>        /bin/echo "1200" >  $i/queue/iosched/write_batch_expire
> done
>
> for i in /sys/block/sd*; do
>        /bin/echo "1024" >  $i/queue/nr_requests
> done
>
> for i in /sys/block/sd*; do
>        /bin/echo "256" >  $i/queue/read_ahead_kb
> done
>
> for i in /sys/block/sd*; do
>        /bin/echo "256" >  $i/queue/max_sectors_kb
> done
>
> for i in /sys/class/scsi_host/host*; do
>        /bin/echo "min_power" >  $i/link_power_management_policy
> done
>
>
>
>
> try to disable each and every unneeded daemon or applets, programs, etc.
>
> by using:
>
> * powertop
> * iotop
> * htop
> * top
> * lsof | grep /home
> * ...
>