{"id":161903,"date":"2026-02-20T17:11:55","date_gmt":"2026-02-20T15:11:55","guid":{"rendered":"https:\/\/prohoster.info\/blog\/novosti-interneta\/razrabotchik-io_uring-vyyavil-v-qemu-problemu-v-50-80-raz-zamedlyavshuyu-fdmon-v-rezhime-prostoya"},"modified":"2026-02-20T17:11:55","modified_gmt":"2026-02-20T15:11:55","slug":"razrabotchik-io_uring-vyyavil-v-qemu-problemu-v-50-80-raz-zamedlyavshuyu-fdmon-v-rezhime-prostoya","status":"publish","type":"post","link":"https:\/\/prohoster.info\/pl\/blog\/news\/razrabotchik-io_uring-vyyavil-v-qemu-problemu-v-50-80-raz-zamedlyavshuyu-fdmon-v-rezhime-prostoya","title":{"rendered":"Programista io_uring ujawni\u0142 problem w QEMU, kt\u00f3ry 50-80 razy spowalnia\u0142 fdmon w trybie bezczynno\u015bci.","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

Jens Axboe, tw\u00f3rca io_uring oraz planist\u00f3w I\/O CFQ, Deadline i Noop, zaproponowa\u0142 do\u0142\u0105czenie do bazy kodu emulatora QEMU \u0142atki, kt\u00f3ra zmniejsza op\u00f3\u017anienia przy korzystaniu z fdmon (monitorowania deskryptor\u00f3w plik\u00f3w) w trybie 'aio=io_uring' od 50 do 80 razy, gdy system znajduje si\u0119 w stanie bezczynno\u015bci. <\/p>\n

Problem wynika\u0142 z przeniesienia operacji ppoll() w stan u\u015bpienia z timeoutem 499 ms, mimo \u017ce by\u0142y dost\u0119pne dane I\/O. Aby wznowi\u0107 wykonanie g\u0142\u00f3wnej p\u0119tli przetwarzania zdarze\u0144, wstrzymanej z powodu ppoll(), zaproponowano \u0142atk\u0119, kt\u00f3ra dodaje do funkcji tworzenia wpisu SQE (Submission Queue Entry) wywo\u0142anie funkcji aio_notify(), kt\u00f3ra wybudza ppoll() z trybu u\u015bpienia. <\/p>\n

Problem pojawi\u0142 si\u0119 podczas test\u00f3w regresyjnych io_uring w maszynach wirtualnych<\/a> z r\u00f3\u017cnymi urz\u0105dzeniami blokowymi. Jens zauwa\u017cy\u0142 przypadkowe pojawianie si\u0119 timeout\u00f3w podczas korzystania z urz\u0105dze\u0144 AHCI\/SATA w trybie 'aio=io_uring', podczas gdy konfiguracje z urz\u0105dzeniami virtio-blk lub nvme zawsze ko\u0144czy\u0142y testy z powodzeniem w oko\u0142o sekund\u0119. Zauwa\u017cono, \u017ce problem dotyczy wszystkich typ\u00f3w urz\u0105dze\u0144 blokowych, ale dla urz\u0105dze\u0144 AHCI\/SATA op\u00f3\u017anienia s\u0105 najbardziej widoczne z powodu u\u017cycia MMIO. <\/p>\n

Jens r\u00f3wnie\u017c opisa\u0142 swoje do\u015bwiadczenie w debugowaniu problemu z u\u017cyciem asystenta AI Claude. Po zidentyfikowaniu scenariusza, kt\u00f3ry odtwarza\u0142 warunki do wyst\u0105pienia timeoutu, przekaza\u0142 dost\u0119pne dane debugowania Claude, da\u0142 dost\u0119p do maszyny wirtualnej i zaproponowa\u0142 okre\u015blenie prawdopodobnych przyczyn ujawnionego b\u0142\u0119du. <\/p>\n

Claude postanowi\u0142 sprawdzi\u0107, czy wydajno\u015b\u0107 spadnie przy u\u017cyciu urz\u0105dzenia virtio-blk i uruchomi\u0142 z nim zaproponowany przez dewelopera destrukcyjny scenariusz, odtwarzaj\u0105cy problem. W trakcie testu pierwsze 128 MB zawarto\u015bci zosta\u0142o usuni\u0119te z urz\u0105dzenia blokowego \/dev\/vda w wirtualnej maszynie. Po tym Claude doszed\u0142 do wniosku, \u017ce problem nie le\u017cy w virtio-blk. Kiedy Jens zwr\u00f3ci\u0142 uwag\u0119 asystentowi AI na usuni\u0119cie cz\u0119\u015bci zawarto\u015bci \/dev\/vda, odpowiedzia\u0142 'Tak, zrobi\u0142em to', a po pro\u015bbie o napraw\u0119 \u2014 przywr\u00f3ci\u0142 funkcjonalno\u015b\u0107 wirtualnego dysku \/dev\/vda. Zauwa\u017cono, \u017ce korzystanie z asystenta AI pomog\u0142o lepiej zrozumie\u0107 charakterystyk\u0119 wykonania r\u00f3\u017cnych cykli przetwarzania zdarze\u0144 w QEMU. <\/p>\n

Warto zauwa\u017cy\u0107, \u017ce problem by\u0142 do\u015b\u0107 trudny do wykrycia, poniewa\u017c w testach syntetycznych op\u00f3\u017anienie nie jest rejestrowane z powodu wp\u0142yni\u0119cia na wyst\u0105pienie b\u0142\u0119du przez obudzenie cyklu przetwarzania zdarze\u0144 z ppoll w wyniku innej aktywno\u015bci, a syntetyczne testy wej\u015bcia\/wyj\u015bcia nie wykonuj\u0105 przetwarzania otrzymanych danych. Op\u00f3\u017anienie sta\u0142o si\u0119 bardziej zauwa\u017calne po dodaniu kilku wywo\u0142a\u0144 usleep() w celu symulacji przetwarzania danych. <\/p>\n

Po naprawie na systemie w stanie spoczynku (idle): time sudo .\/iotest \/dev\/sda Wykonano w 25.76 sekundy fish zewn\u0119trzny usr czas 6.19 millis 783.00 micros 5.41 millis sys czas 12.43 millis 642.00 micros 11.79 millis <\/p>\n

Po naprawie na systemie w stanie spoczynku: time sudo .\/iotest \/dev\/sda Wykonano w 1.30 sekundy fish zewn\u0119trzny usr czas 2.14 millis 0.14 millis 2.00 millis sys czas 16.93 millis 1.16 millis 15.76 millis
\n
\u0179r\u00f3d\u0142o: opennet.ru<\/a> <\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

\u0419\u0435\u043d\u0441 \u042d\u043a\u0441\u0431\u043e (Jens Axboe), \u0441\u043e\u0437\u0434\u0430\u0442\u0435\u043b\u044c io_uring \u0438 \u043f\u043b\u0430\u043d\u0438\u0440\u043e\u0432\u0449\u0438\u043a\u043e\u0432 \u0432\u0432\u043e\u0434\u0430\/\u0432\u044b\u0432\u043e\u0434\u0430 CFQ, Deadline \u0438 Noop, \u043f\u0440\u0435\u0434\u043b\u043e\u0436\u0438\u043b \u0434\u043b\u044f \u0432\u043a\u043b\u044e\u0447\u0435\u043d\u0438\u044f \u0432 \u043a\u043e\u0434\u043e\u0432\u0443\u044e \u0431\u0430\u0437\u0443 \u044d\u043c\u0443\u043b\u044f\u0442\u043e\u0440\u0430 QEMU \u043f\u0430\u0442\u0447, \u0432 50-80 \u0440\u0430\u0437 \u0441\u043e\u043a\u0440\u0430\u0449\u0430\u044e\u0449\u0438\u0439 \u0437\u0430\u0434\u0435\u0440\u0436\u043a\u0438 \u043f\u0440\u0438 \u0440\u0430\u0431\u043e\u0442\u0435 fdmon (file descriptor monitoring) \u0432 \u0440\u0435\u0436\u0438\u043c\u0435 «aio=io_uring» \u0438 \u043d\u0430\u0445\u043e\u0436\u0434\u0435\u043d\u0438\u0438 \u0441\u0438\u0441\u0442\u0435\u043c\u044b \u0432 \u0441\u043e\u0441\u0442\u043e\u044f\u043d\u0438\u0438 \u043f\u0440\u043e\u0441\u0442\u043e\u044f (idle). \u041f\u0440\u043e\u0431\u043b\u0435\u043c\u0430 \u043f\u0440\u043e\u044f\u0432\u043b\u044f\u043b\u0430\u0441\u044c \u0438\u0437-\u0437\u0430 \u043f\u0435\u0440\u0435\u0432\u043e\u0434\u0430 \u043e\u043f\u0435\u0440\u0430\u0446\u0438\u0438 ppoll() \u0432 \u0441\u043e\u0441\u0442\u043e\u044f\u043d\u0438\u0438 \u0441\u043d\u0430 \u0441 \u0442\u0430\u0439\u043c\u0430\u0443\u0442\u043e\u043c 499 […]<\/p>\n","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"author":8,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[702],"tags":[],"class_list":["post-161903","post","type-post","status-publish","format-standard","hentry","category-news"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\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\n","aioseo_head_json":{"title":"\ud83e\udd47Tw\u00f3rca io_uring zidentyfikowa\u0142 problem w QEMU, kt\u00f3ry w 50-80 razy spowalnia\u0142 fdmon w trybie spoczynku | ProHoster","description":"Jens Axboe, tw\u00f3rca io_uring oraz planist\u00f3w wej\u015bcia\/wyj\u015bcia CFQ, Deadline i Noop, zaproponowa\u0142 w\u0142\u0105czenie do bazy kodowej emulatora QEMU \u0142atki, kt\u00f3ra w 50-80 razy zmniejsza op\u00f3\u017anienia podczas pracy fdmon (file.","canonical_url":"https:\/\/prohoster.info\/pl\/blog\/news\/razrabotchik-io_uring-vyyavil-v-qemu-problemu-v-50-80-raz-zamedlyavshuyu-fdmon-v-rezhime-prostoya","robots":"max-image-preview:large","keywords":"","webmasterTools":{"miscellaneous":""},"schema":null,"og:locale":"pl_PL","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\udd47\u0420\u0430\u0437\u0440\u0430\u0431\u043e\u0442\u0447\u0438\u043a io_uring \u0432\u044b\u044f\u0432\u0438\u043b \u0432 QEMU \u043f\u0440\u043e\u0431\u043b\u0435\u043c\u0443, \u0432 50-80 \u0440\u0430\u0437 \u0437\u0430\u043c\u0435\u0434\u043b\u044f\u0432\u0448\u0443\u044e fdmon \u0432 \u0440\u0435\u0436\u0438\u043c\u0435 \u043f\u0440\u043e\u0441\u0442\u043e\u044f | ProHoster","og:description":"\u0419\u0435\u043d\u0441 \u042d\u043a\u0441\u0431\u043e (Jens Axboe), \u0441\u043e\u0437\u0434\u0430\u0442\u0435\u043b\u044c io_uring \u0438 \u043f\u043b\u0430\u043d\u0438\u0440\u043e\u0432\u0449\u0438\u043a\u043e\u0432 \u0432\u0432\u043e\u0434\u0430\/\u0432\u044b\u0432\u043e\u0434\u0430 CFQ, Deadline \u0438 Noop, \u043f\u0440\u0435\u0434\u043b\u043e\u0436\u0438\u043b \u0434\u043b\u044f \u0432\u043a\u043b\u044e\u0447\u0435\u043d\u0438\u044f \u0432 \u043a\u043e\u0434\u043e\u0432\u0443\u044e \u0431\u0430\u0437\u0443 \u044d\u043c\u0443\u043b\u044f\u0442\u043e\u0440\u0430 QEMU \u043f\u0430\u0442\u0447, \u0432 50-80 \u0440\u0430\u0437 \u0441\u043e\u043a\u0440\u0430\u0449\u0430\u044e\u0449\u0438\u0439 \u0437\u0430\u0434\u0435\u0440\u0436\u043a\u0438 \u043f\u0440\u0438 \u0440\u0430\u0431\u043e\u0442\u0435 fdmon (file.","og:url":"https:\/\/prohoster.info\/pl\/blog\/news\/razrabotchik-io_uring-vyyavil-v-qemu-problemu-v-50-80-raz-zamedlyavshuyu-fdmon-v-rezhime-prostoya","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":"2026-02-20T15:11:55+00:00","article:modified_time":"2026-02-20T15:11:55+00:00","article:publisher":"https:\/\/www.facebook.com\/prohoster","article:author":"https:\/\/www.facebook.com\/prohoster"},"aioseo_meta_data":{"post_id":"161903","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":"2026-02-20 15:12:29","breadcrumb_settings":null,"limit_modified_date":false,"reviewed_by":null,"ai":null,"created":"2026-02-20 15:11:55","updated":"2026-02-20 15:12:29","focus_keyword":null,"additional_keywords":null,"truseo_locale":null},"gt_translate_keys":[{"key":"link","format":"url"}],"_links":{"self":[{"href":"https:\/\/prohoster.info\/pl\/wp-json\/wp\/v2\/posts\/161903","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/prohoster.info\/pl\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/prohoster.info\/pl\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/prohoster.info\/pl\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/prohoster.info\/pl\/wp-json\/wp\/v2\/comments?post=161903"}],"version-history":[{"count":1,"href":"https:\/\/prohoster.info\/pl\/wp-json\/wp\/v2\/posts\/161903\/revisions"}],"predecessor-version":[{"id":164173,"href":"https:\/\/prohoster.info\/pl\/wp-json\/wp\/v2\/posts\/161903\/revisions\/164173"}],"wp:attachment":[{"href":"https:\/\/prohoster.info\/pl\/wp-json\/wp\/v2\/media?parent=161903"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/prohoster.info\/pl\/wp-json\/wp\/v2\/categories?post=161903"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/prohoster.info\/pl\/wp-json\/wp\/v2\/tags?post=161903"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}