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Date: Thu, 23 Apr 2015 21:34:59 +1000
From: "Edgar E. Iglesias" <edgar.iglesias@gmail.com>
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Subject: Re: [Qemu-devel] [PATCH v2 9/9] target-arm: Add WFx instruction
 trap support
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: Sergey Fedorov <serge.fdrv@gmail.com>, Alex =?iso-8859-1?Q?Benn=E9e?= <alex.bennee@linaro.org>, QEMU Developers <qemu-devel@nongnu.org>, Greg Bellows <greg.bellows@linaro.org>

On Thu, Apr 23, 2015 at 12:28:43PM +0100, Peter Maydell wrote:
> On 23 April 2015 at 12:24, Edgar E. Iglesias <edgar.iglesias@gmail.com> wrote:
> > Maybe we can consider YIELD instead of NOP when has_work() is true as a WFI
> > is probably a good hint from guests to reschedule QEMU CPUs.
> 
> That I'm not convinced about. If we have a pending interrupt then
> our best bet is probably to take it immediately on this CPU, not
> yield to another CPU and take the interrupt when we eventually
> get control back.

Yeah, true. It's actually a very bad YIELD point when has_work() is true
for a WFI.

For WFE too I guess, when interrupts are unmasked.

Good point.

Cheers,
Edgar