Kamfanin Facebook a kan buɗaɗɗen tushen zanta tebur aiwatar ingantacce don ingantaccen amfani da ƙwaƙwalwar ajiya. Ana amfani da F14 a cikin kayan aikin Facebook azaman maye gurbin yawancin nau'ikan tebur na zanta kuma yana ba ku damar rage yawan ƙwaƙwalwar ajiya ba tare da sadaukar da aikin ba. F14 a bayyane ya zarce google :: sparse_hash_map hash tables, wanda ya zuwa yanzu an dauki mafi kyawun ƙwaƙwalwar ajiya. An rubuta lambar aikin a cikin C++ kuma an haɗa shi a cikin ɗakin karatu .
F14 yana nufin algorithms tare da tsarin ƙudurin karo dangane da hashing sau biyu tare da 14 (ɗaya tantanin halitta na tebur ɗin hash yana adana jerin ramummuka 14, kuma ana ƙididdige tazara tsakanin sel ta amfani da aikin hash na taimako). Don hanzarta ayyukan tacewa ta salula, aiwatarwa yana amfani da umarnin vector SSE2 don tsarin x86_64 da NEON don tsarin Aarch64, waɗanda ke ba ku damar daidaita ayyukan zaɓin ramummuka tare da maɓallan maɓalli da maɓallin nunawa a cikin sarkar. Tubalan 14 ramummuka ana sarrafa su a lokaci guda, wanda shine ma'auni mafi kyau tsakanin ingancin amfani da cache na processor da adadin karo.
Siffar F14 ita ce ikon zaɓar dabarun adana bayanai daban-daban:
- F14NodeMap - yana cinye mafi ƙarancin adadin ƙwaƙwalwar ajiya don manyan maɓalli masu girma da matsakaici. Yana ba da ajiyar abubuwa kai tsaye tare da kira duk lokacin da aka shigar da aikin malloc;
- F14ValueMap - Yana ba da ƙarancin amfani da ƙwaƙwalwar ajiya don ƙananan maɓalli. Ana adana abubuwa a cikin sel kansu (layi). Don matsakaita da manyan maɓallai, wannan hanyar tana kaiwa ga ƙwaƙwalwar ƙwaƙwalwar ajiya da aka sani;
- F14VectorMap yana da sauri don manyan teburi da maɓalli masu rikitarwa, amma a hankali don maɓallai masu sauƙi da ƙananan tebur. An tattara abubuwan a cikin tsararru mai jujjuyawar kuma an yi magana da su ta hanyar ma'anar fihirisa 32-bit;
- F14FastMap dabarun hade ne. Idan maɓallin bai wuce 24 bytes ba, to F14ValueMap an zaɓi, kuma idan ƙari, F14VectorMap an zaɓi.
source: budenet.ru