Scalable QoS-Aware Disk-Scheduling

A r~ew q u a l i ~ of se1-1,ice (QoS) nc1:rtt.e rli.tk sched~rlir~g 01gorirhrn is preserired. 11 is applical~le irl ert~~irarlrnerirs where rlara requests art-i1.e 1virl1 dt'fferer~r QoS r-equir-erner~rs rrch as real-rirne rlearllirie, rrrlrl rrserpriorirj: Pr-e~,io~rs ~liork ori rlisk schedulir~g 110s -fofoc,rr.ted or] o/~rirr~izirlg rhe seek rirnes and/or meeting rl~e real-rirne deodlirres. A nr~jfied frrrniework for QoS disk .rrhehrlir~g is presertred rhar scrrles v~~irli rhe riurnberof sched~rling prrr-ornerer.~. The ger~er-a1 idea is based or1 modeling rhe disk scl~eduler I-equesrs as poirlrs in rhe tnulri-dimer~sior~al space, where each of rke diriier~sioris represetzrs one of rheprrrrrrlleters (e.g.. one rlirnettsio~i reptesetirs rhe request rleadlir~e, trtiothe~I-epr-ese~its rhe disk rj,lit~der tiu~nber; o11d r 111ir.d ditnet~siotr r-epresetirs the pr-iorig of rlze 1-equesr, err.). The11 rlre disk scl~edrrli~~g ptabletn redlrces to rhe pr.oblem of ,firlditrg ( I lirlecrr orrler ro traverse rhese ~nulri-ditnet~sio,,ol poitir; Space,fillitig cur-i:es are adopter1 ro rlqfitie a lit~enr otzler-,forsorritig and schedltlitlg objecrs rhar lie it1 rlie tnulri-ditnetisio,,al space. Tliis get~eralires rile one-di~ne~isio~~al disk schetiuli~~g nlgorirl~tris (e.g., EDE SATE FIFO). Sevel-a1 recht~iqrres are preser~red ro show ho\v a QoS-aware disk scl~etllrlerdeals vvirh rhe progt-essive orrival of requests over ritrie. Sitnrrlariorr e.xperinier7rs are presetired ro sl~oiil a co~npnrisot~ o f rhe alrer~~iarive reclz~~iques arid ro detno~lsrrare the scalabilit?. of r11e proposed QoSaware disk scl~edulitig algor~irhtn o17er. orher rladiriotial ap-