interesting(?) data on network interrupt servicing
John Baldwin
jhb at freebsd.org
Thu Mar 23 18:59:26 UTC 2006
On Thursday 23 March 2006 12:50, Paolo Pisati wrote:
> On Thu, Mar 23, 2006 at 11:12:24AM -0500, John Baldwin wrote:
> > You probably want preemption on to minimize latency.
>
> i'm doing preemption now...
>
> > If this is a
> > UP machine, you should turn SMP off. It might be interesting to
> > compare using 7.x without APIC as well, since you are not using
> > APIC on 4.x.
>
> ok, and what do we expect from it?
> besides interrupt masking/eoi, what are the other areas influenced
> by apic<->8259 switch?
That's probably about it.
> moreover, should i profile the asm part too?
Well, it would be good if you could do that on both 4.x and 7.0 to get
a better comparison. 4.x does most of the equivalent of
intr_execute_handlers() in asm.
>
> APIC 8259
> | |
> | |
> ISR_VEC() INTR()
> | |
> | | we don't take any measure
> ========================================== <= above this threshold...
> lapic_handle_intr() atpic_handle_intr()
> \ /
> \ /
> intr_execute_handlers()
> |
> |
> .
> .
> .
--
John Baldwin <jhb at FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve" = http://www.FreeBSD.org
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