Pages: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
==Hardware== | ==Hardware== | ||
* PAE, page tables, PTEs, TLB -- explain ''FIXME'' | * PAE, page tables, PTEs, TLB, MMU -- explain ''FIXME'' | ||
==Huge Pages== | ==Huge Pages== | ||
Making pages larger means fewer TLB misses for a given TLB size (due to more pages being supportable in the same amount of memory, due to narrower page identifiers), large mapping/releasing operations will be faster (due to fewer page table entries needing to be handled), and less memory is devoted to page table entries for a given amount of memory being indexed. The downside is possible wastage of main memory (due to pages not being used as completely). A 2002 paper from Navarro et al at Rice proposed transparent operating system support: "[http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.3.2392 Transparent Operating System Support for Superpages]". FreeBSD and Solaris support large pages transparently, while applications must explicitly take advantage of them on Linux (through at least 2.6.30). | Making pages larger means fewer TLB misses for a given TLB size (due to more pages being supportable in the same amount of memory, due to narrower page identifiers), large mapping/releasing operations will be faster (due to fewer page table entries needing to be handled), and less memory is devoted to page table entries for a given amount of memory being indexed. The downside is possible wastage of main memory (due to pages not being used as completely). A 2002 paper from Navarro et al at Rice proposed transparent operating system support: "[http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.3.2392 Transparent Operating System Support for Superpages]". FreeBSD and Solaris ("[http://www.sun.com/blueprints/0304/817-5917.pdf support large pages transparently, while applications must explicitly take advantage of them on Linux (through at least 2.6.30). | ||
===Linux=== | ===Linux=== | ||
* They were a [http://lwn.net/Articles/40840/ 2003 Kernel Summit] topic, after seeing first [http://kerneltrap.org/node/418 introduction] in Linux 2.5.36 ([http://linuxgazette.net/155/krishnakumar.html LinuxGazette] primer article) | * They were a [http://lwn.net/Articles/40840/ 2003 Kernel Summit] topic, after seeing first [http://kerneltrap.org/node/418 introduction] in Linux 2.5.36 ([http://linuxgazette.net/155/krishnakumar.html LinuxGazette] primer article) | ||