Onjiniyela abavela ku-Facebook (abavinjelwe eRussian Federation) bashicilele umbiko mayelana nokuqaliswa ngonyaka odlule kobuchwepheshe be-TMO (Transparent Memory Offloading), okuvumela ukonga okubalulekile ku-RAM kumaseva ngokususa idatha yesibili engadingeki emsebenzini kumadrayivu ashibhile, njenge-NVMe. SSD - disks. I-Facebook ilinganisela ukuthi ukusebenzisa i-TMO kungonga u-20 kuya ku-32% we-RAM kuseva ngayinye. Isixazululo sakhelwe ukusetshenziswa kwingqalasizinda lapho izinhlelo zokusebenza zisebenza ezitsheni ezizimele. Izingxenye ze-Kernel-side ze-TMO sezifakiwe ku-Linux kernel.
Ngasohlangothini lwe-Linux kernel, ubuchwepheshe busekelwa uhlelo olungaphansi lwe-PSI (Pressure Stall Information), olutholakala kusukela ngokukhululwa okungu-4.20. I-PSI isivele isetshenziswa kuzibambi zememori ephansi futhi ikuvumela ukuthi uhlaziye imininingwane mayelana nesikhathi sokulinda sokuthola izinsiza ezahlukahlukene (CPU, inkumbulo, I/O). Nge-PSI, amaphrosesa esikhala somsebenzisi angakwazi ukuhlola ngokunembe kakhudlwana amazinga omthwalo wesistimu namaphethini okwehla, okuvumela okudidayo ukuthi kubonakale kusenesikhathi, ngaphambi kokuba kube nomthelela obonakalayo ekusebenzeni.
Esikhaleni somsebenzisi, i-TMO ihlinzekwa ingxenye ye-Senpai, ethi, ngokusebenzisa i-cgroup2, ilungise ngokuguquguqukayo umkhawulo wememori weziqukathi zohlelo lokusebenza ngokusekelwe kudatha etholwe ku-PSI. I-Senpai ihlaziya izimpawu zokuqala kokushoda kwensiza nge-PSI, ihlola ukuzwela kwezinhlelo zokusebenza ekwehleni kokufinyelela kumemori futhi izama ukunquma ubuncane besayizi yememori edingwa isiqukathi, lapho idatha edingekayo ekusebenzeni ihlala ku-RAM, kanye nokuhambisana nayo. idatha exazululwe kunqolobane yefayela noma engasetshenziswa ngokuqondile okwamanje, iphoqeleka ukuba iphumele ekuhlukaniseni okushintshiwe.
Ngakho-ke, ingqikithi ye-TMO iwukugcina izinqubo ekudleni okuqinile mayelana nokusetshenziswa kwenkumbulo, okuphoqelela ukushintshaniswa kwamakhasi enkumbulo angasetshenzisiwe okukhishwa kwawo akuthinti kakhulu ukusebenza (isibonelo, amakhasi anekhodi esetshenziswa kuphela ngesikhathi sokuqala, kanye nokusetshenziswa okukodwa. idatha kunqolobane yediski). Ngokungafani nokukhipha ulwazi ku-swap partition ekuphenduleni ingcindezi yenkumbulo, kudatha ye-TMO ikhishwa ngokusekelwe ekuqaguleni okusebenzayo.
Enye yezindlela zokukhishwa ukungabikho kokufinyelela ekhasini lememori imizuzu emi-5. Amakhasi anjalo abizwa ngokuthi amakhasi enkumbulo ebandayo futhi ngokwesilinganiso akha cishe u-35% wememori yohlelo lokusebenza (kuye ngokuthi uhlobo lohlelo lokusebenza, kukhona uhla olusuka ku-19% kuya ku-65%). I-Preemption icabangela umsebenzi ohlotshaniswa namakhasi ememori angaziwa (inkumbulo enikezwe uhlelo lokusebenza) nememori esetshenziselwa ukugcinwa kwefayela (inikezwe i-kernel). Kwezinye izinhlelo zokusebenza ukusetshenziswa okuyinhloko inkumbulo engaziwa, kodwa kwezinye i-cache yefayela nayo ibalulekile. Ukuze ugweme ukungalingani kokukhishwa kwenqolobane, i-TMO isebenzisa i-algorithm entsha yokuphega ekhipha amakhasi angaziwa namakhasi ahlotshaniswa nenqolobane yefayela ngokulinganayo.
Ukuphushela amakhasi angasetshenziswa kakhulu kwinkumbulo enensayo akunawo umthelela obalulekile ekusebenzeni, kodwa kunganciphisa kakhulu izindleko zehadiwe. Idatha ithululelwa kumadrayivu e-SSD noma endaweni yokushintshana ecindezelwe ku-RAM. Mayelana nezindleko zokugcina i-byte yedatha, ukusebenzisa i-NVMe SSD ishibhile izikhathi eziyi-10 kunokusebenzisa ukucindezela ku-RAM.
Source: opennet.ru