Re: [PATCH 3/6] sched: high-res preemption tick

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed, 2007-10-31 at 22:53 +0100, Andi Kleen wrote:
> Peter Zijlstra <[email protected]> writes:
> 
> > Use HR-timers (when available) to deliver an accurate preemption tick.
> >
> > The regular scheduler tick that runs at 1/HZ can be too coarse when nice
> > level are used. The fairness system will still keep the cpu utilisation 'fair'
> > by then delaying the task that got an excessive amount of CPU time but try to
> > minimize this by delivering preemption points spot-on.
> 
> This might be costly when hrtimers happen to use an more expensive
> to reprogram time source. Even an APIC timer access is fairly slow. 
> And you'll potentially add the to lots of context switces.
> 
> Not sure that is a good idea for performance in general.

Well, me neither, it was just an idea, and a challenge to get
working :-)



-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux