> > The following tests are made with 'IRQ 8' at 95, rtc_wakeup
> at 89(99):
> > * Heavy mmap load, no oom: max jitter: 42.1% ( 51 usec)
> > * Heavy mmap load, oom: max jitter: 11989.2% (14635 usec)
> > (but still "missed irqs: 0", so IRQ 8 was also blocked for 14 ms)
>
> did you get any kernel messages in that time? (about missed
> irqs, etc.)
> Please do a 'dmesg -n 0' to minimize the effect of kernel messages.
Excellent, thanks!
It turned out that the latencies are not caused by the kernel
messages themselves, but by sending them to a serial console
(which was off), in all my high latency cases at rtpri 89(99).
After removing the serial console from the boot parameters,
* the OOM timings are back to normal (around 50 microseconds)
* the USB error and remove timings are back to normal
* the USB plugin timings are in the range of the USB read
(which is up to 1 ms - still bad)
However, latencies at rtprio 2 are still very frustrating
(details will follow).
--
Klaus Kusche
Entwicklung Software - Steuerung
Software Development - Control
KEBA AG
A-4041 Linz
Gewerbepark Urfahr
Tel +43 / 732 / 7090-3120
Fax +43 / 732 / 7090-8919
E-Mail: [email protected]
www.keba.com
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