Re: Measured overhead of timer interrupts

Andi Kleen (ak@muc.de)
22 Jul 1999 16:47:14 +0200


kuznet@ms2.inr.ac.ru writes:

> Hello!
>
> > The networking stuff in particular needs fixing, otherwise
> > the timer values displayed eg by netstat look 'interesting'.
>
> Fix netstat, please, rather than kernel.

It is a kernel bug, HZ is not exported. Actually two, because none of
the /proc should have used it as units, but that cannot be fixed anymore.
It is easy to add a read-only sysctl for HZ though and make netstat use this,
but this won't fix the trillions of other /proc parsers.

> For debugging I want to see variables EXACTLY as they
> look to kernel. The fact that timer value = 1 jiffie
> is critical information.

This can be archived by using a unit that is <= than any jiffie
in use, then you never lose lower bits, just a few (uninteresting)
upper ones. ms is a good candidate.

-Andi

-- 
This is like TV. I don't like TV.

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