Re: USB making time drift [was Re: dynamic-hz]

Gene Heskett
2004-12-16T02:07:46Z

On Wednesday 15 December 2004 13:20, Andrea Arcangeli wrote:
>On Wed, Dec 15, 2004 at 11:44:38AM -0500, Gene Heskett wrote:
>> The HZ=1000 is the culprit?
>
>HZ=1000 isn't the culprit. The culprit is the >1msec latency of the
> usb irq, but that wouldn't be visible with HZ 100 (for this
:> specific case HZ=100 would only be a band-aid).
>
>> Onboard AC-97 audio of course. Crappy stuff... [..]
>
>I doubt it's the chip, but only the motherboard to blame. My laptop
> has the ac97 but no HZ sound out of it.
>
>> translate to 10 millisecond intervals. If you had a 4 millisecond
>> latency,
>> that would be spread over 4 of the 1000 hz interrupts. That
>> sounds rather confusing to the service routine I imagine.
>
>The ones that get confused are the system time and the jiffies, the
> rest of the system can deal with long irq delays. The tick
> adjustment was exactly implemented so that the jiffies and system
> time wouldn't get confused anymore, but it just confuses it the
> other way around in my current experience.
>
>> I'll do that just for grins & report back.
>
>Ok.

Unforch, I was not able to find that in the .config file, so where is
that particular option set?

--
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