FC4 and xen0 performance

[Dave Jones]

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