> * kus Kusche Klaus <[EMAIL PROTECTED]> 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. > > Ingo
I asked our hardware team. The hardware has two devices which are in use and capable of busmaster/DMA transfers: The intel e100 ethernet controller and the intel PIIX4 USB controller. The IDE interface is also a busmaster, but there are only PIO IDE devices. I suspect the latter, as USB reads were running in parallel... How many bytes are transferred at most by the USB controller for a single request? How long may this take? Any experiences / opinitions / advices? Moreover, we know from experience that the "WBINDV" instruction (Write back and invalidate CPU cache) can cause such latencies. Does this instruction occur anywhere in Linux? -- Klaus Kusche (Software Development - Control Systems) KEBA AG Gewerbepark Urfahr, A-4041 Linz, Austria (Europe) Tel: +43 / 732 / 7090-3120 Fax: +43 / 732 / 7090-8919 E-Mail: [EMAIL PROTECTED] WWW: www.keba.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
