>>> Christoph Egger 8-Oct-07 12:54 >>> > > in legacy mode, there is i386 that support 4KB and 4MB page-sizes and > use 2-level pagetables. > in legacy mode, there is i386 PAE that support 4KB and 2MB page-sizes > and use 3-level pagetables. > > in long mode, there is amd64 that support 4KB, 2MB and 1GB page-sizes > and use 4-level pagetables. > > i386 PAE and amd64 use the same paging-mode. > The larger pagetables look like the pagewalk slows down, but actually > the MMU internally does some optimizations that allow jumps w/o modifying > the pages used for the pagetables. > > What is a real speedup is support for the large pages (4MB/2MB) and the > newly introduced giga-pages (1GB) in Barcelona since they > reduce TLB flushes or TLB pressures. > > Oh, and some off-topic hints that also result in speedups: > Fine-graine locking increases speed over the biglock, a better scheduler > that prevents jumping from processes between cpu-cores or even better > between NUMA-nodes.
If you've finished lecturing one of the guys that worked on the original amd64 port of OpenBSD, we look forward to seeing your diffs for fine-grained locking etc. Thanks Tom
