Hi,

Just some additional informations on that topic:

Regarding the performance aspect Christian didn't mention some points that might be important. We also tested connecting the robot to one of the Laptops and just connecting _one_ of the cameras to its gigabit ethernet port. If you then start the camera and the robot task within syskit the delays also occur, and they not just stuck for several milliseconds but up to 8 seconds which causes the driver delivering a time out on the connection to the robot (via serial port) and shuts down the connection completely. I think that it is not "just" a performance issue, the Laptop has quite high performance hardware.

Also on the SeekurJr itself the problem occurs already with one camera running. While the camera is running with 10Fps and binning, the logger has to write ~1MB per Frame which is just 10 MB/s. I did some benchmarking on the harddrive (without system cache) which results in a write performance between 50 - 60 MB/s constantly.

Btw. the aria task and the camera task are not in the same deployment.

So it still could be some performance issue, maybe in combination with unfortunate configured tasks, especially I am not sure about the camera task, as far as I understood the answer from Alex Duda, I guess such a time out
is already used, but maybe Christian can check that better than me.

Regards
Elmar

Am 17.12.2013 08:36, schrieb Matthias Goldhoorn:
On 16.12.2013 19:28, Christian Rauch wrote:
I set the priority by:

task("seekur_drv","aria::Task").priority(99)

which does not affect the result (still delays).

The aria::Task is periodic (100ms) and the camera_ids::Task is triggered in the updateHook after a new image arrives.
I assume both in one deployment. You could (for testing reasons) try to separate the deployments.

As the camera Logger is writing with approx. 10 MB/s (and CPU load is below 20%) which is far away from the HDD limit (~60MB/s) and this whole issue does not occur when running the cameras with logger in syskit and the aria::Task outside syskit, I assume that this is not a hardware related issue.
did you take a look to the load AND the system CPU Usage (top lines from `top`)

As this problem for now seems to occur only when running both tasks (aria, camera_ids) within the bundle; what are the options to change the scheduling by syskit? Does syskit change the behaviour of how processes are scheduled by the OS in any way?
Syskit does NOT influence the scheduling of tasks, this is defined at deployment time implicitly. The only differences when using syskit are:
- Syskit takes also CPU Load
- Syskit might use different connection types than you runscript -> take a look to `syskit instanciate ...` the connection policys are part of the graph

I still assume some load-related problems on your machine, sinc'e you mention that if you stopping the logger everything works fine.

Regards,
Christian


Am 16.12.2013 16:21, schrieb Matthias Goldhoorn:
Several things could happen:

The logger consumes too much time to get out the images, caused by a
slow hdd.
Try to increase the priority level of the pioneer task within your
deployment to make this more urgent from the point of scheduling.

Matthias

P.S. i assume you task is periodic

On 16.12.2013 16:17, Christian Rauch wrote:
Hi,

I am using the aria task within syskit as a device which is supposed to
be called every 100ms. The aria task uses an additional thread
provided by the aria driver to communicate with the robot.

If I run that task from the syskit shell without additional sensors the
updateHook gets called as expected. If I add one or more cameras
(camera_ids) with loggers it happens that the updateHook gets stuck
for some time:

{{{
[DEBUG] - aria::updateHook at: 1386784751.580.629
[DEBUG] - aria::updateHook at: 1386784751.680.668
[DEBUG] - aria::updateHook at: 1386784751.780.542
ArRobotPacketReceiver::receivePacket: bad packet, bad checksum
Warning: Task 'Packet Handler' took 1213 ms to run (longer than the 250
warning time)
Warning: ArRobot sync tasks too long at 1213 ms, (100 ms normal 250 ms
warning)
[DEBUG] - aria::updateHook at: 1386784753.673.374
[DEBUG] - aria::updateHook at: 1386784753.677.372
[DEBUG] - aria::updateHook at: 1386784753.681.379
[DEBUG] - aria::updateHook at: 1386784753.685.211
[DEBUG] - aria::updateHook at: 1386784753.689.226
[DEBUG] - aria::updateHook at: 1386784753.697.023
[DEBUG] - aria::updateHook at: 1386784753.701.405
[DEBUG] - aria::updateHook at: 1386784753.705.386
[DEBUG] - aria::updateHook at: 1386784753.709.383
[DEBUG] - aria::updateHook at: 1386784753.713.216
[DEBUG] - aria::updateHook at: 1386784753.717.292
[DEBUG] - aria::updateHook at: 1386784753.721.253
[DEBUG] - aria::updateHook at: 1386784753.725.392
[DEBUG] - aria::updateHook at: 1386784753.729.400
[DEBUG] - aria::updateHook at: 1386784753.733.392
ArRobotPacketReceiver::receivePacket: bad packet, bad checksum
[DEBUG] - aria::updateHook at: 1386784753.737.227
[DEBUG] - aria::updateHook at: 1386784753.741.226
[DEBUG] - aria::updateHook at: 1386784753.745.274
[DEBUG] - aria::updateHook at: 1386784753.749.305
[DEBUG] - aria::updateHook at: 1386784753.781.249
[DEBUG] - aria::updateHook at: 1386784753.881.453
[DEBUG] - aria::updateHook at: 1386784753.981.492
[DEBUG] - aria::updateHook at: 1386784754.081.523
[DEBUG] - aria::updateHook at: 1386784754.181.392
[DEBUG] - aria::updateHook at: 1386784754.281.428
[DEBUG] - aria::updateHook at: 1386784754.381.462
}}}


For some reason this problem does no longer occur as soon as the camera
loggers are stopped. It also does not occur when the aria Task is
started outside of syskit by using the default deployment and the
TaskInspector or the orocos.rb API.

It looks like the whole task is blocked somehow (the updateHook is not
really taking that much processing time).
Any ideas where this might come from and why this only occurs when
running both tasks with loggers in syskit?

Regards,
Christian




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  Space and Underwater Robotic

  Universität Bremen
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_______________________________________________
Rock-dev mailing list
[email protected]
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--
  Dipl.-Inf. Matthias Goldhoorn
  Space and Underwater Robotic

  Universität Bremen
  FB 3 - Mathematik und Informatik
  AG Robotik
  Robert-Hooke-Straße 1
  28359 Bremen, Germany
Zentrale: +49 421 178 45-6611 Besuchsadresse der Nebengeschäftstelle:
  Robert-Hooke-Straße 5
  28359 Bremen, Germany
Tel.: +49 421 178 45-4193
  Empfang: +49 421 178 45-6600
  Fax:     +49 421 178 45-4150
  E-Mail:[email protected]

  Weitere Informationen:http://www.informatik.uni-bremen.de/robotik


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 Cognitive Robotics
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 Robotics Innovation Center
 Robert-Hooke-Straße 5
 28359 Bremen, Germany
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