On 01.12.10 at 18:33, Jiri Bohac <jbohac@suse.cz> wrote: On Wed, Dec 01, 2010 at 04:56:51PM +0000, Jan Beulich wrote:
On 01.12.10 at 17:08, Greg KH <gregkh@suse.de> wrote: I don't understand what you mean by "run time effect" here. How does having the ipv6 module, or any other module, built into the kernel, have any effect on the runtime speed of the kernel over time?
Increased pressure on TLBs and, less significantly (because of the smaller granularity), caches.
How come? How does code/data mapped in the kernel address space incerease cache/TLB pressure if it is not being accessed?
Unless the used and unused regions of address space are each contiguous (which they certainly aren't), at least the TLBs need to map unused code along with all the used regions. The total size of mapped space is what matters for determining TLB pressure. For the caches, code would likely be separated well enough to mostly avoid bringing in unused bits (apart from the effects of false speculation), but for data the picture may already be different again when considering many small items coming from various components ending up in the same cache line. Jan -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-kernel+help@opensuse.org