From: Ashoka K <ashok.vinu@gmail.com>
To: linux-embedded@vger.kernel.org, linux-newbie@vger.kernel.org
Subject: Need help to measure and tune the latency in Linux RT
Date: Tue, 30 Apr 2013 13:57:21 +0530 [thread overview]
Message-ID: <CALJd4cbfqRFiGHshv8A+0A8kFo_qW=rvREsdgj3jQ=-0Rix0-g@mail.gmail.com> (raw)
Hi,
I have an embedded system running 2.6.33 cross compiled for ARM OMAP
with 1 GHZ uni-processor system.
The application has many threads and processes (around 15 total). In
that 1 thread is time critical and must run every interval confiurable
as 2, 4 or 8 milli sec etc. There is another thread which transfers
Images to a FTP or to HMI etc, whoever requested the image.
With this image transfer enabled my critical process misses the
deadline and timesout. This critical thread is at RR priority 50. I
used a HR timer thread with RR pri 55 to wakeup the critical thread
every 1 milli sec to do the job.
If image transfer is enabled i see that real time thread misses deadlines.
All traffic is flowing on common ethernet connection. Does it affect
in any way ?
How to find out where the kernel is waiting or delaying to schedule
the critical thread even though it is at higher RR priority. How to
measure the latency ?
I am trying to use Oprofile tool, but got some error in cross
compiling. Doesn't these tools add their own latency to the original
problem ?
Any tools ? which one is better. Please provide your input on this.
Regards
Ashoka. K
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next reply other threads:[~2013-04-30 8:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-30 8:27 Ashoka K [this message]
2013-04-30 11:10 ` Need help to measure and tune the latency in Linux RT Jason Cooper
2013-04-30 12:13 ` Stanislav Meduna
2013-04-30 13:17 ` Ashoka K
2013-04-30 12:02 ` ddegraff
[not found] ` <CAPo1LyXaqrGW0rqgvtaEJMoR1Y6NrTdVhV4Jb_gAp_N1ggwu0Q@mail.gmail.com>
2013-05-29 6:02 ` Ashoka K
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