Re: [PATCH 9/11] Panic delay fix

Pavel Machek
2007-02-15T10:17:38Z

Hi!

> >>We'd have to audit and figure out what udelays are for hardware and
> >>which are not, but the evidence is that the vast majority of them are
> >>for hardware and not needed for virtualization.
> >>
> >
> >Which is irrelevant since the hardware drivers won't be used in a
> >virtualised environment with any kind of performance optimisation.
> >
>
> Which is why an audit is irrelevant for the most part. Note on the
> performance below.

You know it is ugly. Alan demonstrated it even hurts performance, but
being ugly is the main problem.

If you _need_ to avoid udelay() in some cases, introduce
udelay_unless_virtualized(), and switch few users to it. Just globaly
defining udelay to nop is _ugly_.
Pavel
--
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