Re: -mm -> 2.6.13 merge status

From: Nish Aravamudan
Date: Wed Jun 22 2005 - 13:04:05 EST

On 6/21/05, Nish Aravamudan <nish.aravamudan@xxxxxxxxx> wrote:
> On 6/21/05, Lee Revell <rlrevell@xxxxxxxxxxx> wrote:
> > On Mon, 2005-06-20 at 23:54 -0700, Andrew Morton wrote:
> > > CONFIG_HZ for x86 and ia64: changes default HZ to 250, make HZ
> > > Kconfigurable.
> > >
> > > Will merge (will switch default to 1000 Hz later if that seems
> > > necessary)
> >
> > Are you serious? You're changing the *default* HZ in a stable kernel
> > series?!?
> >
> > This is a big regression, it degrades the resolution of system calls.
> Not that my opinion should sway anybody else, but I really would
> prefer more of the in-kernel sleep callers were converted to use
> human-time units (and thus were verified to be correct) so that
> switching HZ will result in the *same* latencies. How much of moving
> to lower HZ values is due to the fact that everything is request 10ms
> for 1 jiffy of sleep instead of 1 ms? It's hard to tell if the gain is
> there or from the lower frequency of interrupts.

After some further consideration, I don't think that my patches would
be at all changed by adjusting HZ's default value. I just want to make
sure maintainers are still responsive to appropriate patches to split
time-based delays from tick-based delays. So, CONFIG_HZ is ok by me,
but I consider it a band-aid.

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