Date: Thu, 23 Mar 2006 13:56:40 -0500 From: John Baldwin <jhb@freebsd.org> To: Paolo Pisati <p.pisati@oltrelinux.com> Cc: FreeBSD_Current <freebsd-current@freebsd.org> Subject: Re: interesting(?) data on network interrupt servicing Message-ID: <200603231356.42544.jhb@freebsd.org> In-Reply-To: <20060323175023.GA1039@tin.it> References: <20060322122906.A41691@xorpc.icir.org> <200603231112.26646.jhb@freebsd.org> <20060323175023.GA1039@tin.it>
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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@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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