Messages in this thread | | | Date | Thu, 18 Feb 2010 10:16:03 +0000 | From | Alan Cox <> | Subject | Re: [RFC 1/4] libata: cache device select |
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O> I totally agree with this patch, but question the timings used to justify it. > Surely the overhead is only 1-2usec for the case where the device > is the one that was already selected (on a "smart" interface) ?
IFF you have a smart interface. A lot of the controllers in the PCI space don't appear to be that clever.
> And for the case where the currently selected device is different > than the desired device (the 1msec case), this patch makes little/no difference?
Correct, but even with two devices per cable (which is not the most common setup) you win. Worst case (which I've never seen) you draw.
Alan
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