On Tue, May 26, 2009 at 7:22 PM, Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> wrote: > In theory, one could analyze the Linux kernel to identify the longest > section of code running with preemption disabled, but as far as I know > this has not yet been done. > > So if you need a mathematical proof that your real-time OS will respond > within a bounded time, then RT Linux might not be the right tool for > your job. But a surprisingly large number of RT applications do not > need that level of assurance. > > And I would not be surprised to hear that someone decided to bite the > bullet and actually mechanically analyze the Linux source/binary for > maximum latency. ;-) Hi Antoine, Keep in mind also that in -rt the non-preemptible sections are a very small subset of the kernel code - last time I checked it was just the timer ISR, the scheduler's SCHED_FIFO code, and the stub ISRs for the other interrupts. The rest does not need to be audited for determinism. Of course, for "total determinism" you also have to mathematically prove the hardware behaves as expected... Lee -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
