Re: Minutes from Feb 21 LSE Call

[Andrea Arcangeli]

On Mon, Feb 24, 2003 at 12:56:17AM -0800, Bill Huey wrote:
> On Mon, Feb 24, 2003 at 12:40:05AM -0800, Andrew Morton wrote:
> > There is no evidence for any such thing.  Nor has any plausible
> > theory been put forward as to why such an improvement should occur.
> 
> I find what you're saying a rather unbelievable given some of the
> benchmarks I saw when the preempt patch started to floating around.
> 
> If you search linuxdevices.com for articles on preempt, you'll see a
> claim about IO performance improvements with the patch. If somethings
> changed then I'd like to know.
> 
> The numbers are here:
> 	http://kpreempt.sourceforge.net/

most kernels out there are buggy w/o preempt. 2.4.21pre4aa3 has most of
the needed preemption checks in the kernel loops instead. It's quite
pointless to compare preempt with an otherwise buggy kernel.

Andrea