Improving Direct-Mapped Cache Performance by the Addition of a Small Fully-Associative Cache and Prefetch Buffers. MIT’s Introduction to Algorithms, Lectures 22 and 23: Cache Oblivious Algorithms. This is a happy and sad moment at the same time - I have finally reached the last two lectures of MIT's undergraduate algorithms course.
These last two lectures are on a fairly new area of algorithm research called "cache oblivious algorithms. " Cache-oblivious algorithms take into account something that has been ignored in all the lectures so far, particularly, the multilevel memory hierarchy of modern computers. Retrieving items from various levels of memory and cache make up a dominant factor of running time, so for speed it is crucial to minimize these costs.
The main idea of cache-oblivious algorithms is to achieve optimal use of caches on all levels of a memory hierarchy without knowledge of their size. Cache-oblivious algorithms should not be confused with cache-aware algorithms. The final lecture twenty-three is the most difficult in the whole course and shows cache-oblivious binary search trees and cache-oblivious sorting called funnel sort. Topics covered in lecture twenty-two: Cache Control Directives Demystified. July 2008 by Siddharth Anbalahan | Discuss this article »» (2) Many years ago, HTTP 1.1 introduced specialized Cache Control directives to control the behavior of browser caches and proxy caches.
These were a refinement over the HTTP 1.0 headers that programmers were using to control the behavior of caches. Though these directives are several years old, we still see them being used incorrectly. Pragma: No-cache This is a HTTP 1.0 directive that was retained in HTTP 1.1 for backward compatibility. Notice that “pragma: no-cache” is linked to requests, and not responses. For all practical purposes, you can ignore this directive today. Expires header This is yet another HTTP 1.0 directive that was retained for backward compatibility. In earlier days, developers played a nifty trick with this directive to ensure that a page expires immediately and is not served from the cache: they would set the expiration date to a day in the distant past.
Cache-Control. Un article de Wikipédia, l'encyclopédie libre.
En informatique, le Cache-Control est un en-tête du protocole HTTP concernant la mémoire cache. En effet la plupart des navigateurs web utilisent un espace réservé sur le disque dur pour enregistrer une copie des pages qui sont visitées (souvent). Ainsi quand l'utilisateur demande une page, le navigateur affiche parfois simplement la copie qu'il avait, pour gagner du temps. Le bouton recharger (actualiser, rafraîchir) des navigateurs permet de la mettre à jour. HTTP/1.0[modifier | modifier le code] À ce niveau du protocole, il ne permet qu'un contrôle du cache rudimentaire. Pragma: no-cache[modifier | modifier le code] Permet au navigateur d'indiquer au cache de récupérer le document auprès du serveur d'origine plutôt que de lui renvoyer celui qu'il conserve. HTTP/1.1[modifier | modifier le code] À ce niveau du protocole, l'en-tête Cache-Control offre plus de possibilités. Public[modifier | modifier le code] private[modifier | modifier le code]