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1
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0answers
16 views

Minimizing display lag. Graphics software stack? Process priority? RTOS?

I am looking to come up with a setup to minimize display lag for psycophysics and electrophysiological reaction time experiments. I'm not talking about costly graphics computations on every frame, ...
2
votes
2answers
70 views

What does the change of the clocksource influence?

The output of cat /sys/devices/system/clocksource/clocksource0/available_clocksource lists the available hardware clocks. I have changed the clocks, without any visible difference. sudo /bin/sh -c ...
2
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0answers
35 views

Xenomai: /dev/rtheap is missing

I tried to install Xenomai 2.5.5.2 on my Ubunto 12.04 PC following the steps in this guide. I haven't changed any configuration options. When I run sudo ./trivial-periodic, I get a message saying ...
1
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0answers
23 views

Is it possible to run the 2.4 linux kernel and RTLinux 3.2 on modern hardware? [closed]

I have software written for kernel 2.4 and RTLinux 3.2, but the old hardware started breaking. The software is huge and complicated, so rewriting it for modern hardware is most likely not going to ...
3
votes
1answer
18 views

Real-time executive approach, can be run in desktop Linux?

With the real-time executive approach, a small real-time kernel coexists with the Linux kernel. This real-time core uses a simple real-time executive that runs the non-real-time Linux kernel as its ...
0
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0answers
52 views

The latest stable RT patch version of linux kernel 2.6.31

I want to get the lastest stable RT patch version for linux kernel 2.6.31. But I was confused when looking it up at kernel.org. I saw that: patch-2.6.31.6-rt19.gz last modified was on 10-Nov-2009 ...
0
votes
1answer
47 views

Is there a good way to poll in a real-time process which is kernel friendly?

I have an application which uses boost asio and I would like to use poll() to detect ready network events (packets) and process them as quickly as possible. Additionally, I would like to use ...
2
votes
1answer
63 views

Minimizing hardware interrupts

I am using a modified Linux kernel as a soft real-time OS, on a system that has an architecture like this: CPU1 and CPU2 have 8 cores each. I have 4 processes that need to be run with minimum ...
2
votes
1answer
276 views

Why isn't the -rt (RT-Preempt) kernel patch included by default in the mainline kernel?

According to https://rt.wiki.kernel.org/index.php/RT_PREEMPT_HOWTO , the RT-Preempt patch converts Linux into a fully preemptible kernel. The magic is done by: Making in-kernel locking-primitives ...
4
votes
1answer
101 views

Is there a way to cat files as they are created? [duplicate]

Unlike the answer to this question (Can a bash script be hooked to a file?) I want to be able to see content of files that haven't been created yet as or after they are created. I don't know when ...
3
votes
1answer
209 views

Chrony 506 Cannot talk to daemon

I'm having trouble configuring chrony to sync the time between my raspberry pi and a desktop computer in an isolated network. My raspberry pi's chrony.config file looks like this: server master ...
2
votes
0answers
248 views

how to stop kernel threads preempting real time user space processes?

I created some processes in user space and tried to visualize its working in kernelshark with the trace recorded using trace-cmd. But kernel processes like the ones shown below are preempting my ...
2
votes
1answer
126 views

Linux GUI to track connections made from/to this computer

Is there a GUI to track any socket connection sent to this computer and which program that initiates it? Also if possible track any incoming connection sent to this computer and which program that ...
3
votes
1answer
474 views

Using sched_rt_period_us for setting maximum time between task calls of order of 10ms

I realize sched_rt_period_us and sched_rt_runtime_us are meant to prevent freezing the system in case of runaway RT task. I wonder though, if it's possible to use a small value of sched_rt_period_us ...
1
vote
1answer
102 views

Losing (realtime) permission when sudoing from root to myself

After an upgrade to debian wheezy (I did not upgrade the kernel - it is still 3.8.2) I can no longer start jackd in the way I used to do it. I get you are not allowed to use realtime scheduling. My ...
0
votes
1answer
265 views

Linux distro with PREEMPT_RT patch

I want to know if there is any Linux distribution with PREEMPT_RT kernel patch? If not, is there any good tutorial on how to patch and compile a kernel with RT patch and how can I create kind of a ...
3
votes
2answers
442 views

Why CONFIG_NO_HZ is not set by default

In the Linux Kernel CONFIG_NO_HZ is not set. But an initial reading suggests that setting that option would be nice from a performance point of view. But reading some posts like this made me think ...
2
votes
0answers
85 views

Which counter generates timer interrupts?

I did a iotop to observe the interrupts on my computer. This is the interrupt shown most often. 0 [PIC-edge time] 247 Ints/s (max: 389) I believe it's the timer interrupt, well since ...
1
vote
3answers
155 views

Linux distro to run a MIDI-server on a PII 333 MHz

I am looking for a Linux distro that can be used to redirect MIDI message from the network to the soundboard a TurtleBeach Montego from 1997. Currently the computer is running Windows 98 se and I get ...
1
vote
0answers
512 views

MPlayer benchmarking - realtime FPS counter

I was trying to use MPlayer as a simple benchmarking tools and I need it to show the real time FPS counter, either on the console or on the video playback itself. I googled around and I stumbled ...
1
vote
1answer
520 views

Change of real time priority made no visible effect

we were trying to get the best result with software PWM on raspberry pi with Raspbian. We made a python script which starts PWM on a GPIO pin, and observed the results with the oscilloscope. It ...
7
votes
1answer
516 views

Real time priorities in non real time OS

If I do the following command on my standard Linux Mint installation: comp ~ $ ps -eo rtprio,nice,cmd RTPRIO NI CMD ... 99 - [migration/0] 99 - [watchdog/0] 99 - [migration/1] - 0 ...
4
votes
2answers
763 views

c++ programming on a Real-time linux OS

Is there any gotcha's programming RealTime C++ applications (user space and linux drivers) on RT linux kernel compare to a std linux kernel? The Linux RT patch applies changes to kernel scheduler, ...
9
votes
1answer
667 views

Negatives of running processes with real-time priority?

The question is as the title says, are there any downsides of running processes with real-time priority (chrt -f 99)? My hypothesis is that this combined with an affinity will ensure that any ...
2
votes
3answers
2k views

How to merge output of two running log files in real-time

I have been analysing how a Linux USB driver works using two disparate methods: examining the output of usbmon, which is a hex dump-ish view of what's being sent "on the wire". adding printk() ...
30
votes
15answers
4k views

Run unix command precisely at very short intervals WITHOUT accumulating time lag over time

Question I'd like to be able to run a UNIX command precisely every second over a long time period. I need a solution, which does not lag behind after a certain time, because of the time the command ...
0
votes
1answer
775 views

Hurd vs Plan9 vs Linux vs eCos vs FreeRTOS what are the main differences specially with Hurd?

Hurd is actually not Unix nor Linux. But more superior says. Where Plan9 and Linux are in the range of Unix/Linux. eCos and FreeRTOS is also completely not unix/linux. What is the main differences ...
2
votes
0answers
442 views

Can I apply real time Linux kernel patch on Android kernel?

I would like to apply real time patch on the Android kernel (given I've found Kernel patch for corresponding Kernel version). Is it possible or should I create a patch specifically for the purpose of ...
1
vote
0answers
415 views

error: implicit declaration of function ‘rt_dev_socket’

The developer says: http://comments.gmane.org/gmane.linux.real-time.rtnet.user/2546 Now how can I tell the Makefile to look for headers in /usr/local/rtnet/include respectively ...
0
votes
1answer
301 views

What is the realtime equivalent of the module r8169?

From here: http://www.xenomai.org/index.php/RTnet:Installation_%26_Testing#Testing_with_a_single_node_.28local_loopback.29 TODO: simplify the following steps. - Then you need to edit the file ...
4
votes
1answer
1k views

How to know whether the Linux driver for the real-time network device was built into the kernel?

From here: http://www.xenomai.org/index.php/RTnet:Installation_%26_Testing#Debugging_RTnet The Linux driver for the real-time network device was built into the kernel and blocks the hardware. ...
1
vote
2answers
294 views

System Management Mode in embedded systems

I wish to install Xenomai which works on Linux providing a kind of hard real time environment. x86/64 architectures are supposed to contain the "System Management Mode" which prevents them from being ...
1
vote
1answer
92 views

Command to list in real time all the actions of a process

I cannot remember this command (and googling was unsuccessful), but there is a way to get the list of actions performed by a process, that outputs something like # listprocessactions -p 1234 ...
3
votes
1answer
6k views

Real Time Local File Sync

How can I set up an instant file sync for two local directories? The catch is I need it in real time (15, 10 or even 5 seconds is too slow), and I don't want the target root directory created. For ...
4
votes
1answer
173 views

linux patches related to time measurement accuracy?

Is there a set of patches around for linux kernel that address accuracy of (system, rather than user) process time? i've heard about RTLinux, but i don't really need the actual real-time scheduling ...
8
votes
2answers
2k views

real time backup if file changed?

Are there any linux/unix console applications similar to Yadis that would allow me to: be set up from the console backup multiple directories backup / sync in real time after the files (text files) ...
5
votes
2answers
306 views

Is it possible to record audio directly to a computer's optical drive?

There's a question over at audio.SE at the moment and I thought it may attract some answers here. I asked the user and he's happy to have it posted here to see if anyone has some ideas. Here it is ...
9
votes
2answers
3k views

Advantages of using a RTOS such as QNX or VxWorks instead of Linux?

When developing a solution that requires a real-time operating system, what advantages would an operating system such an QNX or VxWorks have over Linux? Or to put it another way, since these ...
2
votes
4answers
420 views

Is SCADA an RTOS?

Is SCADA one of the RTOS out there (it's used for real-time control and data acquisition)?
3
votes
2answers
773 views

Does the Linux PreemptRT patch benefit desktop users?

Does the PREEMPT_RT patch (real-time kernel) have any benefit for regular desktop users?