Facebook e leka algorithm e ncha ea taolo ea tšubuhlellano ea COPA khahlano le BBR le CUBIC

Facebook e hatisitsoeng liphetho tsa liteko tse nang le algorithm e ncha ea taolo ea tšubuhlellano - KOPANE, e ntlafalitsoeng bakeng sa ho fetisa litaba tsa video. Algorithm e hlahisitsoe ke bafuputsi ba Massachusetts Institute of Technology. Mohlala oa COPA o reriloeng bakeng sa tlhahlobo o ngotsoe ka C++, bula e nang le laesense tlasa MIT mme e kenyellelitsoe ho mvfst - ts'ebetsong ea protocol ea QUIC e ntseng e ntlafatsoa ho Facebook.

Algorithm ea COPA e tsepamisitse maikutlo ho rarolla mathata a hlahang ha o fetisetsa video holim'a marang-rang. Ho ipapisitsoe le mofuta oa video, litlhoko tse batlang li fapane li behiloe ho li-algorithms tsa taolo ea tšubuhlellano - bakeng sa video e sebetsanang, hoa hlokahala ho netefatsa tieho e nyane, esita le ka litšenyehelo tsa boleng, mme ha ho phatlalatsoa video ea boleng bo holimo e lokiselitsoeng esale pele, ho fanoa ka pele. ho boloka boleng. Pejana, bahlahisi ba ts'ebeliso ba ne ba lekantsoe bokhoni ba ho sebelisa li-algorithms tse fapaneng ho latela litlhoko tsa boleng kapa tsa latency. Bafuputsi ba entseng COPA ba lekile ho theha algorithm ea bokahohle bakeng sa ho laola tšubuhlellano ea video ea TCP e ka etsoang ho latela litlhoko tsa video.

Mosebetsi oa algorithm ea taolo ea tšubuhlellano ke ho fumana tekanyo e nepahetseng ha o romella lipakete - ho romela lipakete tse ngata haholo ho ka lebisa tahlehelong ea lipakete le ho senyeha ha ts'ebetso ka lebaka la tlhoko ea ho li romella hape, 'me ho romella butle haholo ho lebisa tieho, eo hape e amang ts'ebetso hampe. . Protocol ea QUIC e khethiloe bakeng sa liteko, kaha e lumella ts'ebetsong ea li-algorithms tsa taolo ea tšubuhlellano sebakeng sa basebelisi ntle le ho kena-kenana le kernel.

Ho thibela tšubuhlellano ea liteishene tsa puisano, COPA e sebelisa mohlala oa litšoaneleho tsa seteishene ho ipapisitse le tlhahlobo ea liphetoho tsa tieho nakong ea ho fana ka lipakete (COPA e fokotsa boholo ba fensetere ea tšubuhlellano ha tieho e ntse e eketseha, e laola hore tieho e qala ho eketseha esita le sethaleng pele tahlehelo ea pakete e etsahala) . Tekanyo pakeng tsa tieho le ho feta e lokisoa ho sebelisoa parameter e khethehileng ea delta. Ho eketseha ha delta ho eketsa kutloelo-bohloko ho tieho empa ho fokotsa ho phalla ha metsi, athe ho fokotseha ha delta ho lumella ho phalla ho holimo ka litšenyehelo tsa ho lieha ho eketseha. Delta = 0.04 e hlalosoa e le tekanyo e nepahetseng pakeng tsa boleng le latency.

Ho ipapisitsoe le ts'ebeletso ea phallo ea Facebook Live, COPA e ile ea lekoa ha e bapisoa le li-algorithms tse tsebahalang tsa CUBIC le BBR. Algorithm ea kamehla ea CUBIC ho Linux ke ho eketsa butle-butle boholo ba fensetere ea tšubuhlellano ho fihlela tahlehelo ea pakete e etsahala, ka mor'a moo boholo ba fensetere bo khutlisetsoa boleng pele tahlehelo e qala.

CUBIC e siea lintho tse ngata tse lakatsehang ho buffering ea lipakete lisebelisoa tsa sejoale-joale tsa marang-rang, tse liehisang marotholi a lipakete. Algorithm ea taolo ea tšubuhlellano ha e tsebe ka ho ferekana 'me e tsoela pele ho eketsa lebelo le haeba kanale e se e ntse e petetsane 'meleng. Lipakete tse sa romelloang li koetsoe ho e-na le ho lahloa, 'me algorithm ea TCP ea ho laola tšubuhlellano e kena feela ha buffer e tletse' me e sitoa ho leka-lekanya sekhahla sa phallo le lebelo la sehokelo sa 'mele. Ho rarolla bothata bona, Google e hlahisitse algorithm e ntlafalitsoeng ea BBR e bolelang esale pele lebelo le fumanehang ka ho hlahloba ka tatellano le khakanyo ea nako ea ho khutla (RTT).

Ka delta=0.04, matšoao a COPA a bile haufi le CUBIC le BBR. Litekong tse entsoeng holim'a khokahanyo ea marang-rang ea lebelo le phahameng le tieho e tlase ea phetisetso ea pakete, COPA e fihletse latency e tlase (479 ms) ha e bapisoa le CUBIC (499 ms), empa e ile ea oela hanyane kamora BBR (462 ms). Ha boleng ba khokahanyo bo fokotseha, COPA e bontšitse liphetho tse ntle ka ho fetisisa - tieho e ne e le tlase ka 27% ho feta ha u sebelisa CUBIC le BBR.

Ka nako e ts'oanang, mocha oa puisano o futsanehileng, COPA le BBR li entse hore ho khonehe ho finyella katleho e phahameng haholo ha e bapisoa le CUBIC. Phaello ea BBR, ha e bapisoa le CUBIC, e ne e le 4.8% le 5.5%, le COPA - 6.2% le 16.3%.

Source: opennet.ru