Messages in this thread | | | Date | Tue, 21 Jun 2005 11:56:30 -0700 | From | Nish Aravamudan <> | Subject | Re: -mm -> 2.6.13 merge status |
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On 6/21/05, Lee Revell <rlrevell@joe-job.com> 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.
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