From: Rajesh Venkataraman <rajesh_venkataraman@trimble.com>
To: xenomai@xenomai.org
Subject: Fwd: Execution time on Xenomai user thread is high
Date: Mon, 13 Sep 2021 10:49:16 -0700 [thread overview]
Message-ID: <CAM4LU5KSZuDzSO0c1S60_29A77Av94yD-mG6t9D+bM-G7tE+8g@mail.gmail.com> (raw)
In-Reply-To: <CAM4LU5LPFJyo78KWZxrgJL4FShUw0AH1kM2kkNFFiow8QqGfTQ@mail.gmail.com>
---------- Forwarded message ---------
From: Rajesh Venkataraman <rajesh_venkataraman@trimble.com>
Date: Mon, Sep 13, 2021 at 10:41 AM
Subject: Re: Execution time on Xenomai user thread is high
To: Greg Gallagher <greg@embeddedgreg.com>
Hi Greg,
Below are the results of the autotune and latency tests. I do not have any
debug features enabled.
Rajesh
== auto-tuning started, period=10[Xenomai] autotune(irqhand) started
00000 ns (may take a while)
irq gravity... 1333 ns[Xenomai] autotune(kthread) started
kernel gravity... 4666 ns
[Xenomai] autotune(uthread) started
user gravity... 6666 ns[Xenomai] autotune finished [1333i/4666k/6666u]
== auto-tuning completed after 43s
== Sampling period: 1000 us
== Test mode: periodic user-mode task
== All results in microseconds
warming up...
RTT| 00:00:01 (periodic user-mode task, 1000 us period, priority 99)
RTH|----lat min|----lat avg|----lat max|-overrun|---msw|---lat best|--lat
worst
RTD| 2.333| 2.938| 7.000| 0| 0| 2.333|
7.000
RTD| 2.333| 3.048| 6.666| 0| 0| 2.333|
7.000
RTD| 2.333| 3.022| 7.000| 0| 0| 2.333|
7.000
RTD| 2.333| 3.007| 7.333| 0| 0| 2.333|
7.333
RTD| 2.332| 3.037| 8.999| 0| 0| 2.332|
8.999
RTD| 2.332| 2.967| 6.666| 0| 0| 2.332|
8.999
RTD| 2.332| 2.943| 6.665| 0| 0| 2.332|
8.999
RTD| 2.332| 2.964| 6.665| 0| 0| 2.332|
8.999
RTD| 2.331| 2.930| 6.665| 0| 0| 2.331|
8.999
RTD| 2.331| 2.981| 11.665| 0| 0| 2.331|
11.665
RTD| 2.331| 3.039| 6.998| 0| 0| 2.331|
11.665
RTD| 2.331| 3.012| 7.664| 0| 0| 2.331|
11.665
RTD| 2.330| 2.941| 6.997| 0| 0| 2.330|
11.665
RTD| 2.330| 2.974| 6.664| 0| 0| 2.330|
11.665
RTD| 2.330| 2.952| 6.330| 0| 0| 2.330|
11.665
RTD| 2.330| 2.961| 6.330| 0| 0| 2.330|
11.665
RTD| 2.330| 2.925| 5.996| 0| 0| 2.330|
11.665
RTD| 2.329| 3.022| 7.996| 0| 0| 2.329|
11.665
RTD| 2.329| 2.959| 6.996| 0| 0| 2.329|
11.665
RTD| 2.329| 3.038| 7.662| 0| 0| 2.329|
11.665
RTD| 2.329| 3.031| 8.662| 0| 0| 2.329|
11.665
RTT| 00:00:22 (periodic user-mode task, 1000 us period, priority 99)
RTH|----lat min|----lat avg|----lat max|-overrun|---msw|---lat best|--lat
worst
RTD| 2.328| 2.982| 7.662| 0| 0| 2.328|
11.665
RTD| 2.328| 3.030| 6.662| 0| 0| 2.328|
11.665
RTD| 2.328| 2.928| 6.328| 0| 0| 2.328|
11.665
RTD| 2.328| 2.911| 5.994| 0| 0| 2.328|
11.665
RTD| 2.327| 2.975| 7.661| 0| 0| 2.327|
11.665
RTD| 2.327| 3.002| 7.327| 0| 0| 2.327|
11.665
RTD| 2.327| 2.977| 7.327| 0| 0| 2.327|
11.665
RTD| 2.327| 2.939| 6.993| 0| 0| 2.327|
11.665
RTD| 2.326| 2.951| 6.660| 0| 0| 2.326|
11.665
RTD| 2.326| 2.938| 7.326| 0| 0| 2.326|
11.665
RTD| 1.993| 2.890| 6.659| 0| 0| 1.993|
11.665
RTD| 0.659| 2.927| 7.659| 0| 0| 0.659|
11.665
RTD| 2.325| 2.947| 6.992| 0| 0| 0.659|
11.665
RTD| 2.325| 3.008| 7.992| 0| 0| 0.659|
11.665
RTD| 2.325| 2.968| 8.325| 0| 0| 0.659|
11.665
RTD| 2.325| 2.971| 6.325| 0| 0| 0.659|
11.665
RTD| 2.324| 2.926| 5.991| 0| 0| 0.659|
11.665
RTD| 2.324| 2.934| 6.991| 0| 0| 0.659|
11.665
RTD| 2.324| 2.947| 6.324| 0| 0| 0.659|
11.665
RTD| 2.324| 2.897| 6.657| 0| 0| 0.659|
11.665
RTD| 2.324| 2.924| 7.657| 0| 0| 0.659|
11.665
RTT| 00:00:43 (periodic user-mode task, 1000 us period, priority 99)
RTH|----lat min|----lat avg|----lat max|-overrun|---msw|---lat best|--lat
worst
RTD| 2.323| 2.937| 6.990| 0| 0| 0.659|
11.665
^C---|-----------|-----------|-----------|--------|------|-------------------------
On Mon, Sep 13, 2021 at 10:11 AM Greg Gallagher <greg@embeddedgreg.com>
wrote:
>
>
> On Mon, Sep 13, 2021 at 1:08 PM Rajesh Venkataraman via Xenomai <
> xenomai@xenomai.org> wrote:
>
>> Hi,
>> We recently ported our application to Linux(4.19.25)/Xenomai from RTOS.
>> We have time critical routines in our application. This routine is run in
>> Xenomai user threads with the highest priority. We run each routine on a
>> core(Affinity to the CPU is set up for the threads). We have a RTDM driver
>> which triggers these routines. We are seeing a maximum/mean latency of
>> 100/25 microseconds respectively from the interrupt assertion to running
>> the real time routine in Xenomai user thread. Our platform is i.MX6 (ARM
>> Cortex-A9 Quad Core) running at 996 MHz. Is that latency reasonable for
>> Xemonai? We are also seeing something strange. The execution time of the
>> real time routines is twice as long as it took on the RTOS. We are not
>> making any calls to the Linux inside these real time routines. The
>> execution time of the routine is 500 microseconds in Xenomai thread. But
>> on
>> an RTOS running this routine in an interrupt context takes only 250
>> microseconds. What is the reason for this higher execution time? Is the
>> xenomai thread getting preempted by some timer irq? Is there a way to
>> avoid
>> this preemption?
>>
>> Rajesh
>
>
> Did you run autotune binary and the latency tests? What were your results?
> How long did you run the latency test for? Do you have any debug features
> enabled?
>
> Thanks
>
> Greg
>
>>
>>
next prev parent reply other threads:[~2021-09-13 17:49 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-13 17:07 Execution time on Xenomai user thread is high Rajesh Venkataraman
2021-09-13 17:11 ` Greg Gallagher
[not found] ` <CAM4LU5LPFJyo78KWZxrgJL4FShUw0AH1kM2kkNFFiow8QqGfTQ@mail.gmail.com>
2021-09-13 17:49 ` Rajesh Venkataraman [this message]
2021-09-14 3:43 ` Greg Gallagher
2021-09-14 5:03 ` Rajesh Venkataraman
2021-09-21 20:28 ` Rajesh Venkataraman
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