svn commit: r186182 - head/sys/dev/ata
Scott Long
scottl at samsco.org
Tue Dec 16 16:16:57 UTC 2008
Alexander Motin wrote:
> Author: mav
> Date: Tue Dec 16 16:04:40 2008
> New Revision: 186182
> URL: http://svn.freebsd.org/changeset/base/186182
>
> Log:
> Call ata_legacy() only once on attach and save it's result. Scanning PCI
> configuration registers (which are not going to change) on every interrupt
> looks expensive, especially when interrupt is shared. Profiling shows me 3%
> of time spent by atapci0 on pure network load due to IRQ sharing with em0.
>
Nice change. PCI Config registers are exceptionally slow to access on
most systems.
Scott
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