Onjiniyela be-Facebook badalule, ngombiko, ukwethulwa kobuchwepheshe I-TMO (Transparent Memory Offloading) ngonyaka odlule, okuyinto ivumela ukonga kakhulu i-RAM kumaseva ngokuhambisa idatha yesibili engadingeki ukusebenza kumadrayivu ashibhile njengama-NVMe SSD.
Facebook ilinganisela ukuthi i-TMO yonga phakathi kuka-20% no-32% we-RAM kuseva ngayinye. Isixazululo sakhelwe ukuthi sisetshenziswe kwingqalasizinda lapho izinhlelo zokusebenza zisebenza ezitsheni ezingazodwa. Izingxenye ze-kernel-side ze-TMO sezivele zifakiwe ku-Linux kernel.
Ohlangothini lwe-Linux kernel, ukusebenza kwezobuchwepheshe ihlinzekwa isistimu engaphansi ye-PSI (Imininingwane Yesitolo Sokucindezela), ehlinzekwe kusukela kunguqulo 4.20.
PSI isivele isetshenziswe kumadrayivu ahlukahlukene angaphandle kwememori futhi ivumela ukuhlaziya ulwazi mayelana nesikhathi sokulinda ukuze uthole izinsiza ezihlukahlukene (CPU, inkumbulo, I/O). Nge-PSI, amaphrosesa wesikhala somsebenzisi angahlola ngokunembe kakhudlwana ukulayishwa kwesistimu namaphethini okunensa, okuvumela okudidayo ukuthi kubonwe ngaphambi kokuba kube nomthelela obonakalayo ekusebenzeni.
Esikhaleni somsebenzisi, ingxenye ye-Senpai isebenzisa i-TMO, elungisa ngokuguqukayo umkhawulo wenkumbulo weziqukathi zohlelo lokusebenza nge-cgroup2 ngokusekelwe kudatha etholwe ku-PSI.
USenpai uhlaziya izimpawu zokuqala zokushoda kwezinsiza nge-PSI, ihlola ukuzwela kwezinhlelo zokusebenza ukunciphisa ukufinyelela kwememori kanye izama ukunquma ubuncane besayizi yememori edingekayo esiqukathi, lapho idatha edingekayo emsebenzini ihlala ku-RAM, kanye nedatha ehlobene ebihlezi kunqolobane yefayela noma engasetshenziswanga ngokuqondile okwamanje, iphoqeleka ukuba iphumele ekuhlukaniseni.
I-Transparent Memory Offload (TMO) yisisombululo se-Meta sezindawo zesikhungo sedatha ezinhlobonhlobo. Yethula indlela entsha ye-Linux kernel ekala umsebenzi olahlekile ngenxa yokushoda kwensiza ku-CPU, inkumbulo, kanye ne-I/O ngesikhathi sangempela. Iqondiswa yilolu lwazi futhi ngaphandle kolwazi lwangaphambili lohlelo, i-TMO ilungisa ngokuzenzakalelayo inani lememori ukuze lilayishwe kudivayisi ehlukahlukene, njengememori ecindezelwe noma i-SSD. Ikwenza lokhu ngokusekelwe kuzici zokusebenza zedivayisi kanye nokuzwela kohlelo lokusebenza ekufinyeleleni okunensa kwememori.
Ngakho-ke, ingqikithi ye-TMO ukugcina izinqubo "ekudleni okuqinile" mayelana nokusetshenziswa kwenkumbulo, okuphoqelela amakhasi enkumbulo angasetshenzisiwe ukuba ahanjiswe ekushintsheni ukwahlukanisa, ukususwa kwawo akuthinti ngokuphawulekayo ukusebenza (ngokwesibonelo, amakhasi anekhodi esetshenziswa kuphela phakathi nokuqaliswa kanye nedatha yesikhathi esisodwa egcinwe kunqolobane kudiski) . Ngokungafani nokuguquguquka kwedatha ekuhlukaniseni okushintshiwe ngokuphendula inkumbulo ephansi, i-TMO ixosha idatha ngokusekelwe ekubikezelweni okubikezelwayo.
Ukungabikho kokufinyelela kukhasi lememori phakathi nemizuzu emi-5 kusetshenziswa njengenye yemibandela yokukhetha. Lawa makhasi abizwa ngokuthi amakhasi abandayo futhi, ngokwesilinganiso, akha cishe u-35% wenkumbulo yohlelo lokusebenza (kuye ngokuthi uhlobo lohlelo lokusebenza, kukhona ukuhluka kusuka ku-19% kuya ku-65%).
Okuthandwayo kucabangela umsebenzi ohlotshaniswa namakhasi enkumbulo angaziwa (inkumbulo enikezwe uhlelo lokusebenza) kanye nenkumbulo esetshenziselwa ukugcinwa kwefayela (inikezwe i-kernel). Kwezinye izinhlelo zokusebenza inkumbulo engaziwa iyona esetshenziswa kakhulu, kodwa kwezinye inqolobane yefayela nayo ibaluleke kakhulu.
Ukuze ugweme ukungalingani lapho ikhipha inkumbulo kunqolobane, i-TMO isebenzisa i-algorithm yokupheja entsha esula amakhasi angaziwa namakhasi ahlotshaniswa nenqolobane yefayela ngokulinganayo.
Ukusunduza amakhasi angasetshenziswa kakhulu kwinkumbulo enensayo akunawo umthelela omkhulu ekusebenzeni, kodwa kunganciphisa kakhulu izindleko zehadiwe. Idatha ithunyelwa kuma-SSD noma isikhala sokushintshaniswa esicindezelwe ku-RAM. Ngezindleko zokugcina i-byte eyodwa yedatha, ukusebenzisa i-NVMe SSD ishibhe izikhathi ezifika kwezi-10 kunokusebenzisa ukucindezela ku-RAM.
Ekugcineni, uma unentshisekelo yokwazi kabanzi ngakho, ungaxhumana nemininingwane Kulesi sixhumanisi esilandelayo.
lokhu kungasetshenziswa kumakhompyutha ajwayelekile anezinhlelo zokusebenza ezijwayelekile?