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
