Messages in this thread | | | Date | Fri, 1 Apr 2005 15:41:27 +0200 | From | Ingo Molnar <> | Subject | Re: 2.6.11, USB: High latency? |
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* kus Kusche Klaus <kus@keba.com> wrote:
> IRQ 7-724 0d..1 1us : end_8259A_irq (do_hardirq) > IRQ 7-724 0d..1 1us!: enable_8259A_irq (do_hardirq) > IRQ 7-724 0d... 832us : do_hardirq (do_irqd) > IRQ 7-724 0d... 833us : trace_irqs_on (do_hardirq)
> mmap-1000 0d.h1 21us : end_8259A_irq (__do_IRQ) > mmap-1000 0d.h1 22us!: enable_8259A_irq (__do_IRQ) > mmap-1000 0d.h. 662us : irq_exit (do_IRQ) > mmap-1000 0d..1 662us : do_softirq (irq_exit)
> mmap-1000 0d.h. 0us : do_IRQ (c012d6d5 7 0) > mmap-1000 0d.h1 2us!: mask_and_ack_8259A (__do_IRQ) > mmap-1000 0d.h1 938us : redirect_hardirq (__do_IRQ) > mmap-1000 0d.h1 939us : wake_up_process (redirect_hardirq)
such 'freezes' almost certainly signal some sort of hardware latency - some device holding the system bus up during DMA. There is no algorithmic reason for any of those steps above to take several hundreds of microseconds.
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