Re: [Bug #11308] tbench regression on each kernel release from2.6.22 -> 2.6.28

[Ingo Molnar]

* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Mon, 17 Nov 2008, David Miller wrote:
> > 
> > The scheduler has accounted for at least %10 of the tbench 
> > regressions at this point, what are you talking about?
> 
> I'm wondering if you're not looking at totally different issues.
> 
> For example, if I recall correctly, David had a big hit on the 
> hrtimers. And I wonder if perhaps Ingo's numbers are without 
> hrtimers or something?

hrtimers should not be an issue anymore since this commit:

| commit 0c4b83da58ec2e96ce9c44c211d6eac5f9dae478
| Author: Ingo Molnar <mingo@xxxxxxx>
| Date:   Mon Oct 20 14:27:43 2008 +0200
|
|     sched: disable the hrtick for now
|    
|     David Miller reported that hrtick update overhead has tripled the
|     wakeup overhead on Sparc64.
|    
|     That is too much - disable the HRTICK feature for now by default,
|     until a faster implementation is found.
|    
|     Reported-by: David Miller <davem@xxxxxxxxxxxxx>
|     Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
|     Signed-off-by: Ingo Molnar <mingo@xxxxxxx>

Which was included in v2.6.28-rc1 already.

	Ingo
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