Iqembu labacwaningi abavela eNyuvesi yaseVirginia kanye naseNyuvesi yaseCalifornia lethule uhlobo olusha lokuhlaselwa kwezakhiwo ezincane zamaphrosesa e-Intel ne-AMD, ahlonzwe ngesikhathi sobunjiniyela obuhlehlayo bamakhono we-CPU angabhaliwe. Indlela yokuhlasela ehlongozwayo ihlanganisa ukusetshenziswa kwe-micro-op cache emaphakathi kuma-processor, engasetshenziswa ukubuyisa ulwazi oluqoqwe phakathi nokuqagelwa kweziyalezo.
Ngezinjongo zokuthuthukisa, iphrosesa iqala ukwenza ezinye iziqondiso ngemodi yokuqagela, ngaphandle kokulinda ukubala okudlule ukuze kuqedwe, futhi uma inquma ukuthi isibikezelo asilungile, ibuyisela ukusebenza esimweni sayo sokuqala, kodwa idatha ecutshungulwe ngesikhathi. ukubulawa okucatshangelwayo kufakwa kunqolobane, okuqukethwe kwayo okunganqunywa.
Kuyaphawuleka ukuthi indlela entsha idlula kakhulu ukuhlasela kwe-Specter v1, yenza ukuhlasela kube nzima ukukubona futhi akuvinjwa izindlela ezikhona zokuvikela ekuhlaselweni kwesiteshi eseceleni okuklanyelwe ukuvimba ubungozi obubangelwa ukukhishwa kweziyalezo okuqagelayo (ngokwesibonelo, ukusetshenziswa yomyalelo we-LFENCE ivimba ukuvuza ezigabeni zokugcina zokuqagela , kodwa ayivikeli ekuvuzeni ngokusebenzisa izakhiwo ezincane).
Indlela ithinta amamodeli we-Intel ne-AMD akhishwe kusukela ngo-2011, okuhlanganisa uchungechunge lwe-Intel Skylake ne-AMD Zen. Ama-CPU anamuhla aphula imiyalelo yephrosesa eyinkimbinkimbi ibe imisebenzi emincane efana ne-RISC, egcinwe kunqolobane ehlukile. Le nqolobane ihluke kakhulu kuzinqolobane ezisezingeni eliphezulu, ayifinyeleleki ngokuqondile futhi isebenza njengesilondolozi sokusakaza sokufinyelela ngokushesha emiphumeleni yokuqopha imiyalo ye-CISC ibe yi-RISC microinstructions. Kodwa-ke, abacwaningi bathole indlela yokudala izimo ezivela lapho izingxabano zokufinyelela kwenqolobane futhi zivumela umuntu ukuba ahlulele okuqukethwe kwenqolobane ye-micro-operation ngokuhlaziya umehluko ngesikhathi sokwenziwa kwezenzo ezithile.
Inqolobane ye-micro-operation kuma-Intel processors ihlukaniswe ngokuphathelene nemicu ye-CPU (Hyper-Threading), kuyilapho ama-AMD Zen processors esebenzisa inqolobane eyabiwe, okudala izimo zokuvuza kwedatha hhayi kuphela ngaphakathi kwentambo eyodwa yokukhipha, kodwa futhi phakathi kwemicu ehlukene ku-SMT. (ukuvuza kwedatha okungenzeka phakathi kwekhodi esebenza kuma-CPU cores ahlukene anengqondo).
Abacwaningi baphakamise indlela eyisisekelo yokuthola izinguquko kunqolobane ye-micro-operation kanye nezimo ezimbalwa zokuhlasela ezivumela ukudala iziteshi zokudlulisa idatha ezifihliwe nokusebenzisa ikhodi esengozini ukuze kuvuze idatha eyimfihlo, kokubili ngaphakathi kwenqubo eyodwa (isibonelo, ukuvuza idatha yokucubungula lapho kwenziwa. Ikhodi yenkampani yangaphandle ezinjinini ezine-JIT nasemishinini ebonakalayo), naphakathi kwe-kernel nezinqubo endaweni yomsebenzisi.
Lapho uhlela okuhlukile kokuhlasela kwe-Specter kusetshenziswa inqolobane ye-micro-operation, abacwaningi bakwazile ukuzuza ukusebenza okungu-965.59 Kbps ngenani lephutha elingu-0.22% no-785.56 Kbps lapho kusetshenziswa ukulungisa iphutha, esimweni sokuhlela ukuvuza ngaphakathi kwekheli elifanayo. indawo kanye nezinga lelungelo. Ngokuvuza okuhlanganisa amazinga elungelo ahlukene (phakathi kwe-kernel nendawo yomsebenzisi), ukusebenza kube ngu-85.2 Kbps nokulungiswa kwamaphutha kanye no-110.96 Kbps ngenani lephutha elingu-4%. Lapho ihlasela amaphrosesa e-AMD Zen, idala ukuvuza phakathi kwama-CPU cores ahlukene anengqondo, ukusebenza kube ngu-250 Kbps ngenani lephutha elingu-5.59% kanye no-168.58 Kbps ngokulungiswa kwamaphutha. Uma kuqhathaniswa nendlela yakudala ye-Specter v1, ukuhlasela okusha kwakushesha izikhathi ezingu-2.6.
Kulindeleke ukuthi ukuvikela ekuhlaselweni kwenqolobane ye-micro-op kuzodinga izinguquko ezizonciphisa ukusebenza kunalapho unike amandla ukuvikela kokuhlasela kwe-Specter. Njengokuyekethisa okuhle, kuhlongozwa ukuthi kuvinjwe ukuhlasela okunjalo hhayi ngokukhubaza ukugcinwa kwesikhashana, kodwa ezingeni lokuqapha okudidayo kanye nokuhlonza izifunda zenqolobane ezijwayelekile zokuhlasela.
Njengasekuhlaselweni kweSpecter, ukuhlela ukuvuza okuvela ku-kernel noma ezinye izinqubo kudinga ukwenziwa kokulandelana okuthile kwemiyalo (amagajethi) ohlangothini lwezinqubo zesisulu, okuholela ekukhishweni kokuqagela kwemiyalelo. Cishe amagajethi afanayo ayi-100 atholwe ku-kernel ye-Linux, ezosuswa, kodwa izindlela zokulungisa isizukulwane sazo zitholakala ngezikhathi ezithile, ngokwesibonelo, ezihlobene nokusebenzisa izinhlelo ze-BPF eziklanywe ngokukhethekile ku-kernel.
Source: opennet.ru