linux-kernel - RE: why kernel implement "udelay" by cpu instructions?

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Message-ID: <C86899CCB10A6C4E93D5978DCB232D4B0D7C0DFE@GDCMX01.igglobal.com>
Date:	Wed, 4 Nov 2009 11:15:01 +0530
From:	"Rajat Jain" <Rajat.Jain@...ogain.com>
To:	"Bryan Donlan" <bdonlan@...il.com>
Cc:	"loody" <miloody@...il.com>, "Rik van Riel" <riel@...hat.com>,
	<linux-kernel@...r.kernel.org>,
	"Kernel Newbies" <kernelnewbies@...linux.org>
Subject: RE: why kernel implement "udelay" by cpu instructions?


Hi,

> 
> I thought hrtimers allow higher-precision wakeups these days?
> Of course, if you only want to sleep for a few microseconds, the
> context switch might take longer than you want to sleep...

Yes, that is right. Sorry, I missed that. But that is purely HW
dependent - if your HW providea a high precision timer (Such as HPET on
latest Intel machines), that can be used for quicker sleeps.

Thanks,

Rajat
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