RE: Latency traces I cannot interpret (sa1100, 2.6.15-rc7-rt1)

From: Daniel Walker
Date: Mon Jan 02 2006 - 16:32:05 EST


On Mon, 2006-01-02 at 08:57 +0100, kus Kusche Klaus wrote:
>
> <idle>-0 0D... 1us+: preempt_schedule_irq (svc_preempt)
> <idle>-0 0.... 5us!: default_idle (cpu_idle)
> <idle>-0 0D..1 8700us+: asm_do_IRQ (c021da48 1a 0)

Your trace appears to be showing an actual latency of 300us . The trace
starts at 8700us . The default_idle line above is showing interrupts are
enable, and preemption is enabled . So the tracing code really should be
ignoring the default_idle line since there is no reason to be tracing.

Daniel

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