Qee lub sij hawm dhau los nws tau paub txog qhov muaj qhov tsis zoo tshiab hauv kev xav txog kev tsim qauv ntawm Intel processors, uas tau hu ua (LVI). Intel muaj nws tus kheej lub tswv yim txog qhov txaus ntshai ntawm LVI thiab cov lus pom zoo rau kev txo qis. Koj tus kheej version ntawm kev tiv thaiv tawm tsam xws li kev tawm tsam engineer ntawm Google. Tab sis koj yuav tau them nyiaj rau kev ruaj ntseg los ntawm kev txo cov processor kev ua tau zoo los ntawm qhov nruab nrab ntawm 7%.
Peb tau sau tseg ua ntej tias qhov txaus ntshai ntawm LVI tsis yog nyob rau hauv cov txheej txheem tshwj xeeb pom los ntawm cov kws tshawb fawb, tab sis nyob rau hauv lub hauv paus ntsiab lus ntawm LVI sab-channel nres, uas tau tshwm sim thawj zaug. Yog li, qhov kev taw qhia tshiab tau qhib rau kev hem thawj uas tsis muaj leej twg tau xav tias yav dhau los (tsawg kawg, qhov no tsis tau tham hauv qhov chaw pej xeem). Yog li ntawd, tus nqi ntawm kev txhim kho Google tus kws tshaj lij Zola Bridges nyob rau hauv qhov tseeb tias nws thaj ua rau txo qis kev txaus ntshai ntawm txawm tias tsis paub txog kev tawm tsam tshiab raws li LVI txoj cai.
Yav dhau los hauv GNU Project Assembler () Cov kev hloov pauv tau ua kom txo qis kev pheej hmoo ntawm LVI qhov tsis zoo. Cov kev hloov no muaj kev ntxiv LFENCE, uas tau tsim kom muaj kev sib tw nruj ntawm kev nco nkag ua ntej thiab tom qab kev thaiv. Kev ntsuas thaj tsam ntawm ib qho ntawm Intel's Kaby Lake cov txheej txheem tsim tau pom tias qhov ua tau zoo txo ββqis txog 22%.
Tus tsim tawm Google tau thov nws thaj nrog ntxiv ntawm LFENCE cov lus qhia rau LLVM compiler teeb, thiab hu ua kev tiv thaiv SESES (Speculative Execution Side Effect Suppression). Txoj kev tiv thaiv nws tau thov kom txo qis LVI kev hem thawj thiab lwm yam zoo sib xws, piv txwv li Spectre V1 / V4. Qhov kev siv SESES tso cai rau lub compiler ntxiv LFENCE cov lus qhia ntawm qhov chaw tsim nyog thaum lub tshuab code tsim. Piv txwv li, ntxig rau lawv ua ntej txhua qhov kev qhia nyeem los ntawm kev nco lossis sau rau hauv kev nco.
LFENCE cov lus qhia tiv thaiv preemption ntawm tag nrho cov lus qhia tom ntej kom txog thaum lub cim xeeb yav dhau los tau nyeem tiav. Obviously, qhov no cuam tshuam rau kev ua haujlwm ntawm processors. Tus kws tshawb fawb pom tias qhov nruab nrab, SESES kev tiv thaiv txo qis kev ua tiav cov haujlwm uas siv lub tsev qiv ntawv tiv thaiv los ntawm 7,1%. Qhov ntau ntawm cov khoom lag luam txo qis hauv qhov no yog li ntawm 4 txog 23%. Cov kws tshawb fawb qhov kev kwv yees thawj zaug yog qhov xav tsis thoob, hu kom nce mus txog 19-fold hauv kev ua haujlwm.
Tau qhov twg los: 3d xov.ru