[Elphel-support] Is there a way to assign a higher priority to an application on the Elphel board?

[Harry Kim]

I just want to see if writing speed to a CF card can significantly change
when a highest priority is assigned to my application.

According to the link, it seems like I can use "renice" instead of nice for
my purpose.

Thanks!

On Thu, Mar 12, 2015 at 5:32 PM, support-list <
support-list at support.elphel.com> wrote:

> Hello Harry,
>
> Which process do you want to have low priority? What kind of problems do
> you have with insufficent CPU power? As we already found the CF card
> timeouts are internal to the card (I noticed similar ~3 sec timeouts with
> the modern SD card we use in the new 10393 camera). The internal buffer is
> set 19MB, so if you know the average compressed frame size (in bytes) and
> the frame rate you may calculate how long the buffer can accumulate data
> without loosing data - normally 19MB should be enough.
>
> There are not many processes that can use much of the CPU (much of the
> activity is inside the kernel), and it depends on the applications you
> really need.
>
> How do you use the images/video from the camera? Do you stream it out over
> the network or record in the camera?
> These two processes are handled by the two different applications, and for
> recording I would suggest to use camogm, not the streamer. If you only
> record, and not stream out simultaneously you may disable streamer
> completely. That will still allow you to acquire images over the network
> with minimal overhead.
>
> There is also an autoexposure daemon running - you may disable it if you
> control the exposure/white balance manually
>
> PHP, web server do not eat up CPU when not specifically requested by the
> host, and there is nothing like Firefox or Flash running in the camera :-)
>
> And yes, default busybox (used in the camera as in most other embedded
> systems) configuration does not have nice command - you may read some
> discussion here: https://communities.intel.com/message/265279
>
> All the above  considerations are for the currently used firmware, really
> old legacy code (more than 6-7 years old) had different applications, FPGA
> clock rate and running software.
>
> Andrey
>
>
>


-- 
Best regards,

Harry Kim
Senior Embedded Software Engineer
RedZone Robotics Inc.
91 43rd Street, Suite 250
Pittsburgh, PA 15201

office 412-927-3456 or 412-476-8980 x214   cell 412-897-0066
hkim at redzone.com
www.redzone.com
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