Re: -mm -> 2.6.13 merge status

From: Nish Aravamudan
Date: Tue Jun 21 2005 - 13:57:40 EST

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.

I've sent out a lot of patches in this direction (using msleep() and
msleep_interruptible() and my soft-timer rework on top of John
Stultz's timeofday rework converts the entire soft-timer subsystem to
use human-time instead of jiffies as it's unit of expiration), but
there is still *a lot* of work left to do :( I will keep sending
patches, but am being pulled in other directions currently.

Just my $.02.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at