Messages in this thread | | | Date | Wed, 2 Sep 1998 03:27:15 -0500 (CDT) | From | Manoj Apte <> | Subject | Re: 2us Interrupt latency's for Linux 2.0.xx |
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> > in a handler). I created my own fast handler registered at IRQ32 ( > > interrupt is generated by > > the APIC timer on a Ppro 200) that gives me a latency of approx 2300 > > nanoseconds > > the APIC timer interrupt is a CPU-internal IRQ, and thus has lower > latencies. It should have identical latencies to a software interrupt. > (like your numbers show). I measured 500 cycles _total_ profiling > interrupt cost. This makes it possible to run 100 thousand IRQs a second > profiling on a 100MHz P5. (i've tried it. It's noticeable but it works) >
Agreed.. but my question was about why i see periodic mega-latencies of the order of 15us every 30 seconds or so. I want to track the source of this, so that _if_ i can dsiable that probelm, I have a much more predictable APIC interrupt latency.
> _external_ interrupts have much higher latencies. (especially as old > XT-PIC interrupts halt the CPU for a considerable amount of time ... this > is not the case with IO-APIC and inter-CPU interrupts.) > > -- mingo >
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