Genode OS Framework
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Martin Stein 8f9355b360 thread API & CPU session: accounting of CPU quota
In the init configuration one can configure the donation of CPU time via
'resource' tags that have the attribute 'name' set to "CPU" and the
attribute 'quantum' set to the percentage of CPU quota that init shall
donate. The pattern is the same as when donating RAM quota.

! <start name="test">
!   <resource name="CPU" quantum="75"/>
! </start>

This would cause init to try donating 75% of its CPU quota to the child
"test".  Init and core do not preserve CPU quota for their own
requirements by default as it is done with RAM quota.

The CPU quota that a process owns can be applied through the thread
constructor. The constructor has been enhanced by an argument that
indicates the percentage of the programs CPU quota that shall be granted
to the new thread. So 'Thread(33, "test")' would cause the backing CPU
session to try to grant 33% of the programs CPU quota to the thread
"test". By now, the CPU quota of a thread can't be altered after
construction. Constructing a thread with CPU quota 0 doesn't mean the
thread gets never scheduled but that the thread has no guaranty to receive
CPU time. Such threads have to live with excess CPU time.

Threads that already existed in the official repositories of Genode were
adapted in the way that they receive a quota of 0.

This commit also provides a run test 'cpu_quota' in base-hw (the only
kernel that applies the CPU-quota scheme currently). The test basically
runs three threads with different physical CPU quota. The threads simply
count for 30 seconds each and the test then checks wether the counter
values relate to the CPU-quota distribution.

fix #1275
2014-11-28 12:02:37 +01:00
doc News item about the first seL4 article 2014-10-30 13:17:37 +01:00
repos thread API & CPU session: accounting of CPU quota 2014-11-28 12:02:37 +01:00
tool prepare_port: log download errors explicitly 2014-11-20 17:06:41 +01:00
.gitignore Qt5: migrate to new ports mechanism 2014-08-22 16:16:40 +02:00
LICENSE Imported Genode release 11.11 2011-12-22 16:19:25 +01:00
README Move repositories to 'repos/' subdirectory 2014-05-14 16:08:00 +02:00
VERSION version: 14.08 2014-08-28 13:36:05 +02:00

                      =================================
                      Genode Operating System Framework
                      =================================


This is the source tree of the reference implementation of the Genode OS
architecture. For a general overview about the architecture, please refer to
the project's official website:

:Official project website for the Genode OS Framework:

  [http://genode.org/documentation/general-overview]

The current implementation can be compiled for 8 different kernels: Linux,
L4ka::Pistachio, L4/Fiasco, OKL4, NOVA, Fiasco.OC, Codezero, and a custom
kernel for running Genode directly on ARM-based hardware. Whereas the Linux
version serves us as development vehicle and enables us to rapidly develop the
generic parts of the system, the actual target platforms of the framework are
microkernels. There is no "perfect" microkernel - and neither should there be
one. If a microkernel pretended to be fit for all use cases, it wouldn't be
"micro". Hence, all microkernels differ in terms of their respective features,
complexity, and supported hardware architectures.

Genode allows the use of each of the kernels listed above with a rich set of
device drivers, protocol stacks, libraries, and applications in a uniform way.
For developers, the framework provides an easy way to target multiple different
kernels instead of tying the development to a particular kernel technology. For
kernel developers, Genode contributes advanced workloads, stress-testing their
kernel, and enabling a variety of application use cases that would not be
possible otherwise. For users and system integrators, it enables the choice of
the kernel that fits best with the requirements at hand for the particular
usage scenario.


Directory overview
##################

The source tree is composed of the following subdirectories:

:'doc':

  This directory contains general documentation. Please consider the following
  document for a quick guide to get started with the framework:

  ! doc/getting_started.txt

  If you are curious about the ready-to-use components that come with the
  framework, please review the components overview:

  ! doc/components.txt

:'repos':

  This directory contains the so-called source-code repositories of Genode.
  Please refer to the README file in the 'repos' directory to learn more
  about the roles of the individual repositories.

:'tool':

  Source-code management tools and scripts. Please refer to the README file
  contained in the directory.


Contact
#######

The best way to get in touch with Genode developers and users is the project's
mailing list. Please feel welcome to join in!

:Genode Mailing Lists:

  [http://genode.org/community/mailing-lists]