Re: io apic + tsc = slowdown (bugreport + possible fix)

[Maciej W. Rozycki]

On Mon, 28 Jun 2004, john stultz wrote:

> Looking closer at the proposed workaround by Maciej posted here:
> http://linux.derkeiler.com/Mailing-Lists/Kernel/2004-04/3174.html
> 
> Why exactly are we using cpu_has_tsc to switch this? I'm not sure I'm
> following how this is TSC dependent. Additionally the comment change
> looks to be from the 2.4 era. 

 One of the two users of timer_ack is do_slow_gettimeoffset().  When the
TSC is selected for use as a high-precision timer do_fast_gettimeoffset()
is used instead.

 Please folks do read the sources sometimes -- I've been repeatedly
clarifying these bits while they are all documented in the sources,
sigh...

  Maciej
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