---------- Forwarded message --------- From: Rajesh Venkataraman <rajesh_venkatara...@trimble.com> Date: Mon, Sep 13, 2021 at 10:41 AM Subject: Re: Execution time on Xenomai user thread is high To: Greg Gallagher <g...@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 <g...@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 > >> >>
