linux v2.6.25.6.cpuisol1

From: Max Krasnyansky
Date: Tue Jun 10 2008 - 20:31:08 EST


This is the latest version of my CPU isolation tree.
Git tree is available at:
git://git.kernel.org/pub/scm/linux/kernel/git/maxk/cpuisol-2.6.25.y.git
http://www.kernel.org/pub/scm/linux/kernel/git/maxk/cpuisol-2.6.25.y.git

Full patch is at:
http://kernel.org/pub/linux/kernel/people/maxk/cpuisol/patches/v2.6.25.6.cpuisol1.patch

In order to simplify overall system setup I wrote a simple tool for system
partitioning - "syspart". You can get the latest version from here
http://kernel.org/pub/linux/kernel/people/maxk/cpuisol/syspart/
git://git.kernel.org/pub/scm/linux/kernel/git/maxk/syspart.git

This tool takes care of setting up IRQ affinities and cpusets, moving kernel
and user space tasks, bring CPUs off/online, etc. Please note that you want to
disable daemons like "irqbalance" to avoid resource partitioning conflicts.
For more info see syspart/README.

--
I also have some sample kernel configs that have been tested and are know to
work. You can pick one of them as base for your kernel:
http://kernel.org/pub/linux/kernel/people/maxk/cpuisol/configs/

Required kernel features:
CONFIG_CGROUP
CONFIG_CPUSETS
CONFIG_CPU_HOTPLUG

Following features are required if you intend on chewing ~100% in the user
space SCHED_FIFO threads running on the isolated CPUs (note that OPROFILE is
known to not work for this use case):
CONFIG_SLUB or CONFIG_SLOB

You may also want to disable the following features in order to achieve the
lowest possible latency:
!CONFIG_HIGH_RES_TIMERS
!CONFIG_NO_HZ
!CONFIG_CPU_FREQ
And of course you want to refer to
http://rt.wiki.kernel.org/index.php/HOWTO:_Build_an_RT-application
for general guidelines on how to build RT applications.

---
This version is based on a completely different approach (compared to previous
cpuisol tree releases). Instead of the centralized cpu_isolation_map it's now
based on the existing kernel features like cpusets. The number of changes is
therefor very small.

Shortlog:
Max Krasnyansky (6):
sched: Fix memory leak in the cpu hotplug handing logic
sched: CPU hotplug events must not destroy scheduler domains created by
the cpusets
genirq: Expose default irq affinity mask (take 3)
sysctl: Add generic cpumask parser for sysctls
stopmachine: Introduce stopmachine_cpus sysctl
Linux 2.6.25.6.cpuisol1

sched: changes are simple bug fixes and are on their way into the mainline.
genirq: stuff has been ACKed in general is pending final ACK from genirq
maintainer.
stopmachine change is a temporary hack to allow for module insertion and removal.

Diffstat:
Documentation/IRQ-affinity.txt | 37 ++++++++++++++----
Documentation/filesystems/proc.txt | 29 +++++++++-----
Makefile | 2 -
arch/alpha/kernel/irq.c | 5 +-
include/linux/irq.h | 14 ++-----
include/linux/sysctl.h | 2 +
kernel/cpuset.c | 6 +++
kernel/irq/manage.c | 28 +++++++++++++-
kernel/irq/proc.c | 59 +++++++++++++++++++++++++++--
kernel/sched.c | 23 +++++++++++
kernel/stop_machine.c | 5 ++
kernel/sysctl.c | 73 +++++++++++++++++++++++++++++++++++
12 files changed, 244 insertions(+), 39 deletions(-)

Comments, questions, suggestions and bug reports are welcome.
Max
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