{"id":104459,"date":"2022-06-21T15:36:41","date_gmt":"2022-06-21T13:36:42","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/facebook-predstavil-mehanizm-tmo-pozvolyayushhij-ekonomit-20-32-pamyati-na-serverah"},"modified":"2022-06-21T15:36:41","modified_gmt":"2022-06-21T13:36:42","slug":"facebook-predstavil-mehanizm-tmo-pozvolyayushhij-ekonomit-20-32-pamyati-na-serverah","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/facebook-predstavil-mehanizm-tmo-pozvolyayushhij-ekonomit-20-32-pamyati-na-serverah","title":{"rendered":"Facebook p\u0159edstavil mechanismus TMO, kter\u00fd umo\u017e\u0148uje u\u0161et\u0159it 20-32 % pam\u011bti na serverech.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

In\u017een\u00fd\u0159i spole\u010dnosti Facebook (zak\u00e1z\u00e1na v Rusk\u00e9 federaci) zve\u0159ejnili zpr\u00e1vu o implementaci technologie TMO (Transparent Memory Offloading) z minul\u00e9ho roku, kter\u00e1 v\u00fdrazn\u011b \u0161et\u0159\u00ed opera\u010dn\u00ed pam\u011b\u0165 na serverech t\u00edm, \u017ee p\u0159esunuje nepot\u0159ebn\u00e1 sekund\u00e1rn\u00ed data na levn\u011bj\u0161\u00ed \u00falo\u017ei\u0161t\u011b, jako jsou NVMe SSD disky. Podle odhadu Facebooku m\u016f\u017ee pou\u017eit\u00ed TMO u\u0161et\u0159it 20 a\u017e 32 % RAM na ka\u017ed\u00e9m serveru. \u0158e\u0161en\u00ed je navr\u017eeno pro pou\u017eit\u00ed v infrastruktur\u00e1ch, kde jsou aplikace spou\u0161t\u011bny v izolovan\u00fdch kontejnerech. Komponenty TMO pracuj\u00edc\u00ed na \u00farovni j\u00e1dra jsou ji\u017e sou\u010d\u00e1st\u00ed j\u00e1dra Linux. <\/p>\n

Na \u00farovni j\u00e1dra Linux zaji\u0161\u0165uje fungov\u00e1n\u00ed technologie subsyst\u00e9m PSI (Pressure Stall Information), kter\u00fd je k dispozici od vyd\u00e1n\u00ed 4.20. PSI se ji\u017e pou\u017e\u00edv\u00e1 v r\u016fzn\u00fdch zpracovatel\u00edch nedostatku pam\u011bti a umo\u017e\u0148uje analyzovat informace o dob\u011b \u010dek\u00e1n\u00ed na z\u00edsk\u00e1n\u00ed r\u016fzn\u00fdch zdroj\u016f (CPU, pam\u011b\u0165, vstup\/v\u00fdstup). Pomoc\u00ed PSI mohou zpracovatel\u00e9 v u\u017eivatelsk\u00e9m prostoru p\u0159esn\u011bji posoudit \u00farove\u0148 zat\u00ed\u017een\u00ed syst\u00e9mu a povahu zpomalen\u00ed, co\u017e umo\u017e\u0148uje odhalen\u00ed odchylek v nejran\u011bj\u0161\u00ed f\u00e1zi, kdy se je\u0161t\u011b znateln\u011b neprojevuj\u00ed na v\u00fdkonu. <\/p>\n

V u\u017eivatelsk\u00e9m prostoru zaji\u0161\u0165uje pr\u00e1ci TMO komponenta Senpai, kter\u00e1 prost\u0159ednictv\u00edm cgroup2 dynamicky upravuje omezen\u00ed pam\u011bti pro kontejnery aplikac\u00ed na z\u00e1klad\u011b dat z\u00edskan\u00fdch z PSI. Senpai analyzuje zn\u00e1mky nedostatku zdroj\u016f p\u0159es PSI, hodnot\u00ed citlivost aplikac\u00ed na zpomalen\u00ed p\u0159\u00edstupu k pam\u011bti a sna\u017e\u00ed se ur\u010dit minim\u00e1ln\u00ed pot\u0159ebnou velikost pam\u011bti pro kontejner, p\u0159i kter\u00e9 pot\u0159ebn\u00e1 data z\u016fst\u00e1vaj\u00ed v RAM a souvisej\u00edc\u00ed data, kter\u00e1 jsou ulo\u017eena ve \u0444\u0430\u0439\u043b\u043e\u0432\u00e9m \u043a\u0435\u0448i nebo nejsou pr\u00e1v\u011b pou\u017e\u00edv\u00e1na, jsou p\u0159esouv\u00e1na do swapu.

\"Facebook<\/center> <\/p>\n

Podstata TMO spo\u010d\u00edv\u00e1 v udr\u017eov\u00e1n\u00ed proces\u016f na p\u0159\u00edsn\u00e9 diet\u011b co se t\u00fd\u010de spot\u0159eby pam\u011bti, a to t\u00edm zp\u016fsobem, \u017ee nedostate\u010dn\u011b vyu\u017e\u00edvan\u00e9 str\u00e1nky pam\u011bti jsou vynucen\u011b p\u0159esunuty do swapu, p\u0159i\u010dem\u017e jejich vy\u0159azen\u00ed nem\u00e1 znateln\u00fd vliv na v\u00fdkon (nap\u0159\u00edklad str\u00e1nky s k\u00f3dem pou\u017e\u00edvan\u00fdm pouze p\u0159i inicializaci a jednor\u00e1zov\u011b pou\u017e\u00edvan\u00e1 data v diskov\u00e9 cache). Na rozd\u00edl od vy\u0159azen\u00ed informac\u00ed do swapu jako reakce na nedostatek pam\u011bti, v TMO jsou data p\u0159esouv\u00e1na na z\u00e1klad\u011b p\u0159edb\u011b\u017en\u00e9 predikce. <\/p>\n

Jedn\u00edm z krit\u00e9ri\u00ed pro vy\u0159azen\u00ed je absence p\u0159\u00edstupu ke str\u00e1nce pam\u011bti po dobu 5 minut. Tyto str\u00e1nky se ozna\u010duj\u00ed jako studen\u00e9 (cold memory page) a pr\u016fm\u011brn\u011b tvo\u0159\u00ed p\u0159ibli\u017en\u011b 35 % pam\u011bti aplikac\u00ed (v z\u00e1vislosti na typu aplikac\u00ed se pohybuje mezi 19 % a\u017e 65 %). P\u0159i vy\u0159azen\u00ed se zohled\u0148uje aktivita spojen\u00e1 s anonymn\u00edmi str\u00e1nkami pam\u011bti (pam\u011b\u0165 p\u0159id\u011blen\u00e1 aplikace) a pam\u011bt\u00ed pou\u017e\u00edvanou pro ke\u0161ov\u00e1n\u00ed soubor\u016f (kterou p\u0159id\u011bluje j\u00e1dro). V n\u011bkter\u00fdch aplikac\u00edch je hlavn\u00ed spot\u0159eba spojena s anonymn\u00ed pam\u011bt\u00ed, ale v jin\u00fdch hraje velkou roli i souborov\u00fd cache. Aby se p\u0159ede\u0161lo nerovnov\u00e1ze p\u0159i vy\u0159azen\u00ed pam\u011bti do cache, v TMO se pou\u017e\u00edv\u00e1 nov\u00fd algoritmus swapov\u00e1n\u00ed, kter\u00fd vy\u0159azuje anonymn\u00ed str\u00e1nky a str\u00e1nky spojen\u00e9 se souborov\u00fdm cache \u00fam\u011brn\u011b. <\/p>\n

Vy\u0159azen\u00ed z\u0159\u00eddka pou\u017e\u00edvan\u00fdch str\u00e1nek do pomalej\u0161\u00ed pam\u011bti nem\u00e1 v\u00fdrazn\u00fd vliv na v\u00fdkon, ale umo\u017e\u0148uje v\u00fdrazn\u011b sn\u00ed\u017eit n\u00e1klady na hardware. Data jsou p\u0159esouv\u00e1na na SSD disky nebo do komprimovan\u00e9 oblasti swapu v opera\u010dn\u00ed pam\u011bti. Co se t\u00fd\u010de n\u00e1klad\u016f na uchov\u00e1n\u00ed jednoho bajtu dat, pou\u017eit\u00ed NVMe SSD je a\u017e 10kr\u00e1t levn\u011bj\u0161\u00ed ne\u017e vyu\u017eit\u00ed komprese v opera\u010dn\u00ed pam\u011bti.

\"Facebook<\/center>
\n
Zdroj: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0418\u043d\u0436\u0435\u043d\u0435\u0440\u044b \u0438\u0437 \u043a\u043e\u043c\u043f\u0430\u043d\u0438\u0438 Facebook (\u0437\u0430\u043f\u0440\u0435\u0449\u0435\u043d\u0430 \u0432 \u0420\u0424) \u043e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043b\u0438 \u043e\u0442\u0447\u0451\u0442 \u043e \u0432\u043d\u0435\u0434\u0440\u0435\u043d\u0438\u0438 \u0432 \u043f\u0440\u043e\u0448\u043b\u043e\u043c \u0433\u043e\u0434\u0443 \u0442\u0435\u0445\u043d\u043e\u043b\u043e\u0433\u0438\u0438 TMO (Transparent Memory Offloading), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0435\u0439 \u0437\u043d\u0430\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e \u044d\u043a\u043e\u043d\u043e\u043c\u0438\u0442\u044c \u043e\u043f\u0435\u0440\u0430\u0442\u0438\u0432\u043d\u0443\u044e \u043f\u0430\u043c\u044f\u0442\u044c \u043d\u0430 \u0441\u0435\u0440\u0432\u0435\u0440\u0430\u0445 \u0437\u0430 \u0441\u0447\u0451\u0442 \u0432\u044b\u0442\u0435\u0441\u043d\u0435\u043d\u0438\u044f \u043d\u0435 \u0442\u0440\u0435\u0431\u0443\u0435\u043c\u044b\u0445 \u0434\u043b\u044f \u0432\u044b\u043f\u043e\u043b\u043d\u0435\u043d\u0438\u044f \u0440\u0430\u0431\u043e\u0442\u044b \u0432\u0442\u043e\u0440\u0438\u0447\u043d\u044b\u0445 \u0434\u0430\u043d\u043d\u044b\u0445 \u043d\u0430 \u0431\u043e\u043b\u0435\u0435 \u0434\u0435\u0448\u0451\u0432\u044b\u0435 \u043d\u0430\u043a\u043e\u043f\u0438\u0442\u0435\u043b\u0438, \u0442\u0430\u043a\u0438\u0435 \u043a\u0430\u043a NVMe SSD-\u0434\u0438\u0441\u043a\u0438. \u041f\u043e \u043e\u0446\u0435\u043d\u043a\u0435 Facebook, \u043f\u0440\u0438\u043c\u0435\u043d\u0435\u043d\u0438\u0435 TMO \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u0435\u0442 \u044d\u043a\u043e\u043d\u043e\u043c\u0438\u0442\u044c \u043e\u0442 20 \u0434\u043e 32% […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":1,"featured_media":104460,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-104459","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\n","aioseo_head_json":{"title":"\ud83e\udd47Facebook p\u0159edstavil mechanismus TMO, kter\u00fd umo\u017e\u0148uje u\u0161et\u0159it 20-32 % pam\u011bti na serverech | ProHoster","description":"In\u017een\u00fd\u0159i ze spole\u010dnosti Facebook (zak\u00e1zan\u00e9 v RF) publikovali zpr\u00e1vu o implementaci technologie TMO (Transparent Memory Offloading), kter\u00e1 v\u00fdrazn\u011b \u0161et\u0159\u00ed opera\u010dn\u00ed pam\u011b\u0165 na serverech.","canonical_url":"https:\/\/prohoster.info\/cs\/blog\/news\/facebook-predstavil-mehanizm-tmo-pozvolyayushhij-ekonomit-20-32-pamyati-na-serverah","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"cs_CZ","og:site_name":"ProHoster | \u041a\u0443\u043f\u0438\u0442\u044c \u043d\u0430\u0434\u0435\u0436\u043d\u044b\u0439 \u0445\u043e\u0441\u0442\u0438\u043d\u0433 \u0434\u043b\u044f \u0441\u0430\u0439\u0442\u043e\u0432 \u0441 \u0437\u0430\u0449\u0438\u0442\u043e\u0439 \u043e\u0442 DDoS, VPS VDS \u0441\u0435\u0440\u0432\u0435\u0440\u044b","og:type":"article","og:title":"\ud83e\udd47Facebook \u043f\u0440\u0435\u0434\u0441\u0442\u0430\u0432\u0438\u043b \u043c\u0435\u0445\u0430\u043d\u0438\u0437\u043c TMO, \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0438\u0439 \u044d\u043a\u043e\u043d\u043e\u043c\u0438\u0442\u044c 20-32% \u043f\u0430\u043c\u044f\u0442\u0438 \u043d\u0430 \u0441\u0435\u0440\u0432\u0435\u0440\u0430\u0445 | ProHoster","og:description":"\u0418\u043d\u0436\u0435\u043d\u0435\u0440\u044b \u0438\u0437 \u043a\u043e\u043c\u043f\u0430\u043d\u0438\u0438 Facebook (\u0437\u0430\u043f\u0440\u0435\u0449\u0435\u043d\u0430 \u0432 \u0420\u0424) \u043e\u043f\u0443\u0431\u043b\u0438\u043a\u043e\u0432\u0430\u043b\u0438 \u043e\u0442\u0447\u0451\u0442 \u043e \u0432\u043d\u0435\u0434\u0440\u0435\u043d\u0438\u0438 \u0432 \u043f\u0440\u043e\u0448\u043b\u043e\u043c \u0433\u043e\u0434\u0443 \u0442\u0435\u0445\u043d\u043e\u043b\u043e\u0433\u0438\u0438 TMO (Transparent Memory Offloading), \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u044e\u0449\u0435\u0439 \u0437\u043d\u0430\u0447\u0438\u0442\u0435\u043b\u044c\u043d\u043e \u044d\u043a\u043e\u043d\u043e\u043c\u0438\u0442\u044c \u043e\u043f\u0435\u0440\u0430\u0442\u0438\u0432\u043d\u0443\u044e \u043f\u0430\u043c\u044f\u0442\u044c \u043d\u0430 \u0441\u0435\u0440\u0432\u0435\u0440\u0430\u0445 \u0437\u0430 \u0441\u0447\u0451\u0442.","og:url":"https:\/\/prohoster.info\/cs\/blog\/news\/facebook-predstavil-mehanizm-tmo-pozvolyayushhij-ekonomit-20-32-pamyati-na-serverah","og:image":"https:\/\/prohoster.info\/wp-content\/uploads\/2021\/11\/logo-350.jpg","og:image:secure_url":"https:\/\/prohoster.info\/wp-content\/uploads\/2021\/11\/logo-350.jpg","og:image:width":350,"og:image:height":350,"article:published_time":"2022-06-21T13:36:42+00:00","article:modified_time":"2022-06-21T13:36:42+00:00","article:publisher":"https:\/\/www.facebook.com\/prohoster","article:author":"https:\/\/www.facebook.com\/prohoster"},"aioseo_meta_data":{"post_id":"104459","title":null,"description":null,"keywords":null,"keyphrases":null,"primary_term":null,"canonical_url":null,"og_title":null,"og_description":null,"og_object_type":"default","og_image_type":"default","og_image_url":null,"og_image_width":null,"og_image_height":null,"og_image_custom_url":null,"og_image_custom_fields":null,"og_video":null,"og_custom_url":null,"og_article_section":null,"og_article_tags":null,"twitter_use_og":false,"twitter_card":"default","twitter_image_type":"default","twitter_image_url":null,"twitter_image_custom_url":null,"twitter_image_custom_fields":null,"twitter_title":null,"twitter_description":null,"schema":{"blockGraphs":[],"customGraphs":[],"default":{"data":{"Article":[],"Course":[],"Dataset":[],"FAQPage":[],"Movie":[],"Person":[],"Product":[],"ProductReview":[],"Car":[],"Recipe":[],"Service":[],"SoftwareApplication":[],"WebPage":[]},"graphName":"","isEnabled":true},"graphs":[]},"schema_type":"default","schema_type_options":null,"pillar_content":false,"robots_default":true,"robots_noindex":false,"robots_noarchive":false,"robots_nosnippet":false,"robots_nofollow":false,"robots_noimageindex":false,"robots_noodp":false,"robots_notranslate":false,"robots_max_snippet":null,"robots_max_videopreview":null,"robots_max_imagepreview":"large","priority":null,"frequency":null,"local_seo":null,"seo_analyzer_scan_date":null,"breadcrumb_settings":null,"limit_modified_date":false,"reviewed_by":null,"ai":null,"created":"2022-06-21 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