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bdec3dd668
The trace_fs server provides access to a Trace_session by using a
File_system_session as frontend.
Each trace subject is represented by a directory ('thread_name.subject')
that contains specific files ('active', 'cleanup', 'enable', 'events',
'buffer_size' and 'policy'), which are used to control the tracing
process of the thread as well as storing the content of its trace
buffer.
The tracing of a thread is only activated if there is a valid policy
installed and the intend to trace the subject was made clear by writing
'1' to the 'enable' file.
The tracing of a thread may be deactived by writing a '0' to the
'enable' file.
A policy may be changed by overwriting the currently used one. In this
case the old policy is replaced by the new policy and is automatically
utilize.
Writing a value to the 'buffer_size' file changes the appointed size of
the trace buffer. This value is only evaluted by reactivating the
tracing process.
The content of the trace buffer may be accessed by reading from the
'events' file. Throughout all tracing session new trace events are
appended to this file.
Nodes of UNTRACED subjects are kept as long as they do not change their
tracing state to DEAD. In this case all nodes are removed from the
file system. Subjects that were traced before and are now UNTRACED will
only be removed by writing '1' to the 'cleanup' file - even if they
are DEAD by now.
To use the trace_fs a config similar to the following may be used:
! <start name="trace_fs">
! <resource name="RAM" quantum="128M"/>
! <provides><service name="File_system"/></provides>
! <config>
! <policy label="noux -> trace" interval="1000" subject_limit="512" trace_quota="64M" />
! </config>
! </start>
'interval' sets the periode in which the Trace_session is polled. The
time is given in milliseconds.
'subject_limit' speficies how many trace subject should by acquired at
most when the Trace_session is polled.
'trace_quota' is the amount of quota the trace_fs should use for the
Trace_session connection. The remaing amount of RAM quota will be used
for the actual nodes of the file system and the 'policy' as well as the
'events' files.
In addiition there are 'buffer_size' and 'buffer_size_limit' that define
the initial and the upper limit of the size of a trace buffer.
Tracing of parent processes or rather threads may be enabled by setting
'parent_levels' to a value greater than '0' (though this attribute is
available, the trace session component within core still lacks support
for it).
A ready-to-use runscript can by found in 'ports/run/noux_trace_fs.run'.
Fixes #1049.
=================================
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 Genode 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
:'base':
This directory contains the source-code repository of the fundamental
frameworks and interfaces of Genode. Furthermore, it contains the generic
parts of core.
:'os':
This directory contains the non-base OS components such as the init process,
device drivers, and basic system services.
:'demo':
This directory contains the source-code repository of various services and
applications that we use for demonstration purposes. For example, a graphical
application launcher called Launchpad and the Scout tutorial browser.
:'base-<platform>':
These directories contain platform-specific source-code repositories
complementing the 'base' repository. The following platforms are supported:
:'linux':
Linux kernel (both x86_32 and x86_64)
:'nova':
NOVA hypervisor developed at University of Technology Dresden
See [http://genode.org/documentation/platforms/nova]
:'foc':
Fiasco.OC is a modernized version of the Fiasco microkernel with a
completely revised kernel interface fostering capability-based
security. It is not compatible with L4/Fiasco.
See [http://genode.org/documentation/platforms/foc]
:'hw':
The hw platform allows the execution of Genode on bare ARM hardware
without the need for a separate kernel. The kernel functionality is
included in core.
See [http://genode.org/documentation/platforms/hw]
:'okl4':
OKL4 kernel (x86_32 and ARM) developed at Open-Kernel-Labs.
See [http://genode.org/documentation/platforms/okl4]
:'pistachio':
L4ka::Pistachio kernel developed at University of Karlsruhe.
See [http://genode.org/documentation/platforms/pistachio]
:'fiasco':
L4/Fiasco kernel developed at University of Technology Dresden.
See [http://genode.org/documentation/platforms/fiasco]
:'codezero':
Codezero microkernel developed by B-Labs
See [http://genode.org/documentation/platforms/codezero]
:'host':
Pseudo platform documenting the interface between the generic and
platform-specific parts of the base framework. This is not a functional
base platform.
:'tool':
Source-code management tools and scripts. Please refer to the README file
contained in the directory.
:'hello_tutorial':
Tutorial for creating a simple client-server scenario with Genode. This
repository includes documentation and the complete source code.
:'libports':
This source-code repository contains ports of popular open-source libraries
to Genode, most importantly the C library. The repository contains no
upstream source code but means to download the code and adapt it to Genode.
For instructions about how to use this mechanism, please consult the README
file at the top level of the repository. Among the 3rd-party libraries
are Qt5, libSDL, freetype, Python, ncurses, Mesa, and libav.
:'dde_linux':
This source-code repository contains the device driver environment for
executing Linux device drivers natively on Genode. Currently, this
repository hosts the USB stack.
:'linux_drivers':
Deprecated version of the Linux device driver environment featuring audio
drivers and the Intel GEM driver. This repository is in a transitionary
phase. Its functionality will be incorporated into 'dde_linux'.
:'dde_ipxe':
This source-code repository contains the device-driver environment for
executing drivers of the iPXE project.
:'dde_oss':
This source-code repository contains the device-driver environment for the
audio drivers of the Open Sound System (OSS).
:'qt4':
This source-code repository contains the Genode version of Qt4 framework.
Please find more information about using Qt4 with Genode in the repository's
'README' file. Please note that the Qt4 support is deprecated. Use Qt5
as contained in 'libports' instead.
:'ports':
This source-code repository hosts ports of 3rd-party applications to
Genode. The repository does not contain upstream source code but provides
a mechanism for downloading the official source distributions and adapt
them to the Genode environment. The used mechanism is roughly the same
as used for the 'libports' repository. Please consult 'libports/README'
for further information.
:'ports-<platform>':
These platform-specific source-code repositories contain software that
capitalizes special features of the respective kernel platform.
For the Fiasco.OC platform, 'ports-foc' hosts a port of the L4Linux
kernel. For further information, please refer to the README file at the
top level of the respective repository.
:'gems':
This source-code repository contains Genode applications that use
both native Genode interfaces as well as features of other high-level
repositories, in particular shared libraries provided by 'libports'.
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]