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Phase-Support, Featured
Updated Feb 4, 2010 by fgx...@gmail.com

some advice: we can modify some Linux system params to improve the device I/O perfomance.

for example: /proc/sys/vm/dirty_writeback_centisecs

echo "100" > /proc/sys/vm/dirty_writeback_centisecs

/proc/sys/vm/dirty_ratio

echo '10' > /proc/sys/vm/dirty_ratio

/proc/sys/vm/dirty_background_ratio

echo '5' > /proc/sys/vm/dirty_background_ratio

Comment by project member fgx...@gmail.com, Nov 2, 2008
Comment by dark...@gmail.com, Dec 8, 2008

Not Found The requested URL /read.php was not found on this server. :-(

Comment by joshl...@gmail.com, Apr 7, 2009

powertop, the laptop tool, recommends 1500 for this:

vm.dirty_writeback_centisecs = 1500

Also, in most distros, you can set these values in /etc/sysctl.conf

vm.dirty_ratio = 10 vm.dirty_background_ratio = 5

Comment by hen...@henriknordstrom.net, Jul 22, 2009

powertop recommendations is for least power consumption, not best performance.

For good smooth performance you want writebacks to be running quite frequently, pushing out the writes in small chunks, not large batches which suddenly hog the device for considerable time.

Laptop requirements is the exact opposite.. here you want writes to be written out in as large batches as feasible to save power at the expense of some uneven latency.


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