FC4 and xen0 performance
Dave Jones
davej at redhat.com
Wed Apr 6 13:15:50 UTC 2005
On Wed, Apr 06, 2005 at 01:18:52PM +0200, Arjan van de Ven wrote:
> On Wed, 2005-04-06 at 07:06 -0400, Alan Cox wrote:
> > On Tue, Apr 05, 2005 at 11:53:33AM -0700, Jeffrey Buell wrote:
> > > results are pretty ugly compared to a 2.6.1 install. FC4 ranges from 1.5X to
> > > 20X slower, while xen0 is about 2X to 6X slower. Is this expected? I'm
> > > looking for configuration differences now, but I'm wondering if anybody can
> >
> > The fork ones are expected yes. The newest kernels have four level page tables
> > and while this allows for huge 64bit systems it has a cost and there is
> > optimisation work left to do.
> >
> > I've not checked the kernel config options but if you look at the src.rpm you
> > can see what debug is enabled
>
> early test kernels usually have all debugging stuff enabled that will
> have a HUGE performance hit in such benchmarks. But that is why it is
> test1 and not the final release...
The expensive stuff (CONFIG_PAGE_ALLOC) is now off for test2.
SLAB_DEBUG is still on, but as you know, thats nowhere near as
expensive.
Dave
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