Symbiotic Jobscheduling for a Simultaneous Multithreading Processor：（共生Jobscheduling同步多线程处理器）.pdfVIP

Symbiotic Jobscheduling for a Simultaneous Multithreading Processor Allan Snavely Dean M. Tullsen University of California, San Diego University of California, San Diego 9500 Gilman Drive 9500 Gilman Drive La Jolla, California 92093-0505 La Jolla, California 92093 allans@ tullsen@ ABSTRACT in hardware for resources every cycle jobs move in and out Simultaneous Multithreading machines fetch and execute in of the running set at the discretion of the OS at a much structions from multiple instruction streams to increase sys coarser granularity In this situation the jobsc heduler de tem utilization and sp eedup the execution of jobs When cides which jobs should b e coscheduled in the running set there are more jobs in the system than there is hardware to supp ort simultaneous execution the op erating system The term symbiosis has b een used to refer to the eective scheduler must cho ose the set of jobs to coschedule ness with which multiple jobs achieve sp eedup when co executed on multithreaded machines Jobs in an SMT This pap er demonstrates that p erformance on a hardware pro cessor can conict with each other on various shared sys multithreaded pro cessor is sensitive to the set of jobs that tem resources Throughput may actually go up or down are coscheduled by the op erating system jobscheduler Thus dep ending on how well the jobs in the running set symbios the full b enets of SMT hardware can only b e achieved if the or