RE: [Xen-devel] how can native driver response quickly for low FIFO device

["Dong, Eddie" <eddie.dong@xxxxxxxxx>]

Keir Fraser wrote:
> On 25 May 2006, at 15:21, Dong, Eddie wrote:
> 
>> Oo, understand UART is handled by Xen, Is this because of this
>> reason? or for debug/console use, and how about other devices?
>> If a user has an PCI card with 8 UART in the box, will we have
>> problem? thx,eddie
> 
> Oh, now I see your point. Yes, for any serial device not handled by
> Xen you could have a scheduling problem. Other examples include
> telephony interface cards and their drivers (e.g., zaptel).
> Higher-rate UARTs do tend to support bigger FIFOs in hardware though.
> Best bet if it really matters is to dedicate a logical processor to
> the domain that owns the hardware.
> 
Yes :-)
 Fortunately most devices in modern computer has either big FIFO or DMA
support.
Those kind of low FIFO device will be headache in VM environment.
Dedicated LP is a good choice, further more HT can take the advantage
here :-)
Eddie

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