Intel 5-level paging: Difference between revisions

Content deleted Content added
Update link. Specify that the volume in question is volume 3A, and give updated document page numbers rather than raw PDF page numbers.
Drawbacks: Citing the proceedings of a conference without giving either a paper name or a page/page range is less useful than ideal. Cite what appears to be the intended paper, using {{cite conference}}. Add parameters.
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== Drawbacks ==
Adding another level of indirection makes [[page table]] "walks" longer.<ref>{{Cite bookconference|title=CSALT: Context Switch Aware Large TLB|book-title=MICRO-50 : the 50th Annual IEEE/ACM International Symposium on Microarchitecture : proceedings : October 14-18, 2017, |___location=Cambridge, MA|otherspublisher=Institute of Electrical and Electronics Engineers., IEEE Computer Society., ACM Special Interest Group on Microprogramming|isbndoi=978145034952910.1145/3123939.3124549|___locationpage=New450|isbn={{format York, New YorkISBN|9781450349529}}|oclc=1032337814|date = 14 October 2017}}</ref> A page table walk occurs when either the processor's [[memory management unit]] or the memory management code in the operating system navigates the tree of page tables to find the [[page table entry]] corresponding to a virtual address.<ref>{{Cite web|url=http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0301h/I1026235.html|title=ARM Information Center|website=infocenter.arm.com|access-date=2018-04-26}}</ref><ref name="x86-software-developers-manual">{{Cite book|url=https://www.intel.com/content/www/us/en/developer/articles/technical/intel-sdm.html|title=Intel® 64 and IA-32 Architectures Software Developer's Manual|volume=3A|publisher=[[Intel Corporation]]}}</ref>{{Rp|page=4{{hyp}}22}} This means that, in the worst case, the processor or the memory manager has to access physical memory six times for a single virtual memory access, rather than five for the previous iteration of x86-64 processors. This results in slightly reduced memory access speed.<ref name="cse-451-paging-tlbs-slides" /> In practice this cost is greatly mitigated by caches such as the [[translation lookaside buffer]] (TLB).<ref name="cse-451-paging-tlbs-slides">{{Cite web|url=https://courses.cs.washington.edu/courses/cse451/08au/lectures/10-paging_TLBs.pdf|title=CSE 451: Operating Systems: Paging & TLBs|last=Levy|first=Hank|author-link=Hank Levy (computer scientist)|date=Autumn 2008|website=[[University of Washington]]|access-date=26 April 2018}}</ref> Further extensions may reduce page walks by using 4096 128-bit page table entries, and allow a larger 64&nbsp;KB [[Page (computer memory)|page size]] and backward compatibility with 4&nbsp;KB page operations.<Ref name=VA64>{{cite patent | country = US | number = 9858198 | status = patent | title = 64KB page system that supports 4KB page operation | pridate = 2015-06-26 | fdate = 2015-06-26 | pubdate = 2016-12-29 | gdate = 2018-01-02 | invent1 = Larry Seiler | assign1 = Intel Corp.}} </ref>
 
== References ==