From kernel@kolivas.org Wed Jun 16 21:22:36 2004
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Date: Wed, 16 Jun 2004 21:22:36 +1000
From: Con Kolivas <kernel@kolivas.org>
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Subject: 2.6.7-ck1
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Patchset update. The focus of this patchset is on system responsiveness with
emphasis on desktops, but the scope of scheduler changes now makes this pat=
ch=20
suitable to servers as well.

http://kernel.kolivas.org

Includes
Staircase scheduler v7.0 (unchanged resync of v6.E)
Extra scheduling policies for staircase:
 Isochronous scheduling - low latency non-privileged (ie soft real time)
 Batch scheduling - idle scheduling
Autoregulated VM swappiness
Supermount-NG v2.04

Changes:
Staircase scheduler and all policies for scheduler updated
Autoregulated swappiness updated to bias exponentially much more like a rea=
l=20
world system.

Removed:
Sched domains merged into mainline
Hyperthread nice merged into mainline
CFQ I/O elevator merged into mainline
CDDMA merged into mainline
Bootsplash - dropped; patch getting too old to safely merge
Reiser4 - dropped; patch too old
Grsecurity option - dropped; unknown future and breaks SMP
IO Prio - not part of current CFQ scheduler; await new version


Sysctl options:
Staircase scheduler can be set for different workloads:

echo 0 > /proc/sys/kernel/interactive
will disable interactive tasks from having bursts, thus being even stricter=
=20
about nice levels (suitable for non gui desktop usage or a server)

echo 1 > /proc/sys/kernel/compute
makes round robin intervals much longer, delays task preemption and disables
interactive mode to optimise cpu cache usage - suitable for computational
intensive tasks.

Autoregulated swappiness:
echo 0 > /proc/sys/vm/autoswappiness
disables the autoregulated swappiness thus allowing you to set
swappiness manually as exists in mainline

Using schedtool ( http://freshmeat.net/projects/schedtool/?topic_id=3D136 )=
 you=20
can enable the different scheduling policies:

schedtool -I -e xmms
or
schedtool -I $pid

will start xmms as an "Isochronous" scheduled task. Alternatively if a task
tries to get real time scheduling but you do not have priviliges for RT=20
it will drop the task to SCHED_ISO.

schedtool -B -e setiathome

will start setiathome as a "Batch" scheduled task. This means it will=20
not get cpu time unless the cpu is completely idle. Note this is _not_=20
suitable for tasks that are disk intensive as a held semaphore can lead to =
a=20
DoS.

Con
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