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Re: [Qemu-devel] Re: [PATCH 0/4] pci: interrupt status/interrupt disable
Re: [Qemu-devel] Re: [PATCH 0/4] pci: interrupt status/interrupt disable support
Thu, 26 Nov 2009 12:41:03 +0000
KMail/1.12.2 (Linux/2.6.30-2-amd64; KDE/4.3.2; x86_64; ; )
> No, this would slow us down because these are per-pin.
> We need a sum of interrupts so that config space
> can be updated by a single command.
> Interrupts are a fastpath, extra loops there should be avoided.
It's really not that much of a fast path. Unless you're doing something
particularly obscure then even under heavy load you're unlikely to exceed a
few kHz. Compared to the average PIC implementation, and the overhead of the
actual CPU interrupt, I find it hard to believe that looping over precisely 4
entries has any real performance hit.
[Qemu-devel] Re: [PATCH 0/4] pci: interrupt status/interrupt disable support, Michael S. Tsirkin, 2009/11/26