Re: do_gettimeofday vs. rdtsc in the scheduler
Andi Kleen (firstname.lastname@example.org)
Wed, 18 Sep 2002 01:52:09 +0200
On Tue, Sep 17, 2002 at 04:32:46PM -0700, David S. Miller wrote:
> From: john stultz <email@example.com>
> Date: 17 Sep 2002 16:32:15 -0700
> Additionally, where is this system tick thing? You make it sound like
> its a register in the cpu, and while the Ultra-III may have one, I'm
> unaware of a system/bus tick register on intel chips. Is it in some
> semi-documented MSR?
> It's in a register on Ultra-III. The whole point of this
> conversation, if you read my initial postings, is that
> "this should have been specified in the x86 architecture"
> I know full well it isn't currently :-)
Sorry, it's wrong. The x86 architecture has several such registers
(apic timers, 8253 timer, HPET [Microsoft requires this for new
hardware that will be w*s certified])
They just all suck on various systems or in general. HPET is ok,
but still not widespread enough.
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