Henry Bausley wrote: > Is there any way the kernel mode interrupt handling maximum times can be > decreased. I very much need to reduce my kernel mode interrupt > latencies. I know my hardware is capable of better performance based > upon measurements done with RT Linux. Below is our timing comparison, > all times are the maximums. > > > Xenomai 2.4.5 interrupt handler w/ Kernel 2.6.26 powerpc, gcc 4.2 > ------------------------------------------------------------------- > AMCC 440EP - 24.5 usec > AMCC 460EX - 16.5 usec >
While running long performances tests on a Sequoia board here (I'm still investigating the latency trace data and evaluating optimizations), I've never been able to reproduce such worst case latency values. The figures I have on the 440EPx (w/ 2.6.26 + Xenomai 2.4.5 + I-pipe 2.2-07 + ELDK-4.2 toolchain) are: klatency: 15.2 us latency -t2 : 17.1 us latency -t1: 26.1 us latency -t0: 34.9 us /proc/xenomai/latency reset to 0 (no timer shot anticipation) continuous process creation loop and interrupt flood on entry. The figure you are most likely interested in - the one that actually compares with RTLinux's latency test - is given by the klatency test, i.e. pure in-kernel timer handler, no user-space Xenomai thread). Could you tell us a bit more about your kernel config, and the kind of stress you put on the system? TIA, > > FSM Labs RT-Linux 2.2 w/ Kernel 2.6.14 ppc, gcc 3.3 > --------------------------------------------------- > AMCC 440EP - 10.0 usec > AMCC 460EX - Not Available, would require 10's of thousands of dollars > to WindRiver > > > > > _______________________________________________ > Xenomai-help mailing list > [email protected] > https://mail.gna.org/listinfo/xenomai-help > -- Philippe. _______________________________________________ Xenomai-help mailing list [email protected] https://mail.gna.org/listinfo/xenomai-help
