On Tue, Apr 13, 2010 at 12:35 AM, Andrew Snow <a...@modulus.org> wrote:
> > The statements about the scheduler flipping between cores is also somewhat > false, ULE does the right thing now for long-running computational threads. > > Furthermore, I can't see how a Gflops benchmark which fits in the CPU cache > has anything to do with the memory architecture of the operating system. > > It can. Search the web for descriptions of page coloring. Roughly speaking, if your cache is physically indexed, the way in which the virtual memory system allocates physical pages to virtual addresses can affect whether or not the cache is fully utilized. In a pathological case, those physical pages that your application touches reside in the same part of the cache and consequently you suffer frequent conflict misses. Meanwhile, the other parts of the cache go unused. Page coloring creates a predictable mapping between virtual and physical addresses so that a carefully written application can avoid the pathological case. Our support for superpages has the same effect. Alan _______________________________________________ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
