Re: [Xen-devel][RFC]degradation on IPF due to hypercall set irq

[Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>]

On 22/11/06 7:43 am, "Xu, Anthony" <anthony.xu@xxxxxxxxx> wrote:

> Batching multicall may be a good idea,
> The only question is how and when we batch xc_evtchn_notify and set_level
> hypercall,
> 
> When xc_evtchn_notify is called, there may be several set_level hypercall
> should be called,
> But set_level hypercall is based on irq line level, how to "remember" several
> set_level hypercalls?
> Maybe we need to change set_level hypercall interface.

Have an array of set_level hypercall structures, and an array of multicall
structures. Fill them in at the point we currently do the hypercall. Flush
when:
 A) the array is already full; or
 B) when qemu passes through its event loop.

Make the arrays 16 entries large, for example, will be plenty.

Use the same mechanism for the notification (i.e., add to the multicall
array, to be flushed by qemu's main loop).

 -- Keir



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