Re: [Fwd: Re: [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.4]

From: Ingo Molnar
Date: Sat Oct 30 2004 - 06:18:20 EST



* Lee Revell <rlrevell@xxxxxxxxxxx> wrote:

> 835 80000000 0.473ms (+0.000ms): finish_task_switch (__schedule)
> 835 80000000 0.474ms (+0.000ms): trace_stop_sched_switched (finish_task_switch)
> 835 80000000 0.474ms (+0.849ms): (835) ((49))
> 835 80000000 1.324ms (+0.000ms): do_IRQ (finish_task_switch)
> 835 80000000 1.324ms (+0.001ms): do_IRQ ((0))
> 835 80000000 1.325ms (+0.002ms): mask_and_ack_8259A (__do_IRQ)

this seems to be very similar to the DMA problems Mark H Johnson had. It
is almost certainly not caused by the kernel. It could in theory be some
SMM overhead, but the bigger likelyhood is disk DMA.

Ingo
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