QpuInterruptHandler
is a class that helps Qt programs to receive an intimation when an
interrupt occurs. QpuInterruptHandler does this by working in tandem
with a kernel module (qpu_irq_reporter) and Qt's QSocketNotifier class.
The QpuInterruptHandler
project consists of the following
The
qpu_irq_reporter device
driver. This module provides a character device driver that is at the
heart of this project. It assumes the following responsibilities
It
records information about
interrupts as and when they occor in the system.
It provides a character device interface using which user space
programs can register the IRQs they are interested in. qpu_irq_reporter
reports interrupt occurance events for only those IRQs that are
registered by the user program.
It implements the poll method of the character device driver so that
user space programs can synchronously poll for interrupt occurances
QpuInterruptHandler
class
which
Provides
methods for
registering and unregistering IRQ's
Uses QSocketNotifier to poll for interrupt occurance events reported by
the qpu_irq_reporter device driver. Since QSocketNotifier works with
Qt's event loop; we can be sure that QpuInterruptHandler does not
__interrupt__ Qt programs; but only reports interrupt occurances in a
synchronous manner
QpuInterruptToSignal class
which
Is a subclass of
QpuInterruptHandler
Emits a signal each time an interrupt occurance is detected
Using the classes and
device driver described above; an example program
was written which allows IRQ occurance inspection. Take a look at the
screenshot below.
User can select (list
box on the left) the IRQ's he is interested in;
and the graph on the right graphs the rate of occurance of the IRQ's. I
know the UI is not very informative; but the example program is only
used for demonstration.
Download and
Install
Before reading ahead download
a copy of QpuInterruptHandler project: qpuirq.tar.gz.
After downloading the tar.gz file; untar it and you will get two
directories
kmodule: Kernel Module for the qpu_irq_reporter device driver
sources: Implementation of QpuInterruptHandler and QpuInterruptToSignal
classes (along with the example program)
Compiling The Kernel
Module (qpu_irq_reporter) The kernel module is in the
kmodule subdirectory of this directory. To
compile the kernel module in this directory execute the following
command
[root@localhost
]$ cd ./kmodule[root@localhost ]$ make -C
<kernel-source-directory-path> SUBDIRS=`pwd` modules
Just
replace <kernel-source-directory-path> with the absolute path to
the directory where you have the kernel sources installed on your
system.
On
my system I have kernel
sources installed here /usr/src/kernels/2.6.11-1.1369_FC4smp-i686/, so
the command I use is
[root@localhost
]$ make -C /usr/src/kernels/2.6.11-1.1369_FC4smp-i686/ SUBDIRS=`pwd`
module
Loading
the Kernel Module
Once the module
is compiled then execute the following command
[root@localhost ]$ insmod qpu_irq_reporter.ko
Creating
Device Node for accessing the module
Use the
following command to find out the major number of the device
you have just loaded
