Re: [Bug #11308] tbench regression on each kernel release from 2.6.22-> 2.6.28

[Linus Torvalds]

On Mon, 17 Nov 2008, David Miller wrote:

> From: Ingo Molnar <mingo@xxxxxxx>
> Date: Mon, 17 Nov 2008 12:01:19 +0100
> 
> > The scheduler's overhead barely even registers on a 16-way x86 system 
> > i'm running tbench on. Here's the NMI profile during 64 threads tbench 
> > on a 16-way x86 box with an v2.6.28-rc5 kernel [config attached]:
> 
> Try a non-NMI profile.
> 
> It's the whole of the try_to_wake_up() path that's the problem.

David, that makes no sense. A NMI profile is going to be a _lot_ more 
accurate than a non-NMI one. Asking somebody to do a clearly inferior 
profile to get "better numbers" is insane.

We've asked _you_ to do NMI profiling, it shouldn't be the other way 
around.

		Linus
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