Messages in this thread | | | Subject | Re: Latency data - 2.6.14-rc3-rt13 | From | Sven-Thorsten Dietrich <> | Date | Tue, 11 Oct 2005 01:56:19 -0700 |
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On Mon, 2005-10-10 at 20:45 -0700, Mark Knecht wrote: > On 10/10/05, Mark Knecht <markknecht@gmail.com> wrote: > > > > ( softirq-timer/0-3 |#0): new 3997 us maximum-latency critical section. > > So the root cause of this 4mS delay is the 250Hz timer. If I change > the system to use the 1Khz timer then the time in this section drops, > as expected, to 1mS. > > ( softirq-timer/0-3 |#0): new 998 us maximum-latency critical section. > => started at timestamp 121040020: <acpi_processor_idle+0x20/0x379> > => ended at timestamp 121041019: <thread_return+0xb5/0x11a> > > So, thinking very interesting here I think. >
Maximum preemption latencies near the timer period are sometimes indicative of mismatched preempt_disable/preempt_enable pairs in the code.
Usually the scheduler warns about that on the console, however.
Sven
> Back to the drawing board as to my xruns. > > - Mark > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ -- *********************************** Sven-Thorsten Dietrich Real-Time Software Architect MontaVista Software, Inc. 1237 East Arques Ave. Sunnyvale, CA 94085
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