PinIt: Influencing OS Scheduling via Compiler-Induced Affinities
Girish Mururu, Kangqi Ni, Ada Gavrilovska, Santosh Pande · 2023
In multi-core machines, applications execute in a complex-co-execution environment in which the number of concurrently executing applications typically exceed the number of available cores. In order to fairly and efficiently utilize cores, modern operating systems (OS) such as Linux migrate threads between cores during execution. Although such thread migrations alleviate the problem of stalling and load balancing yielding better core utilization, they also tend to destroy data locality, resulting in fewer cache hits, TLB hits, and thus performance loss for the group of applications collectively. This problem is especially severe in embedded servers which execute media and vision applications that exhibit high data locality. One one hand, mitigating this problem across a group of applications based on OS only solution is infeasible since OS treats applications as blackboxes and has no knowledge of its locality and other behavior. On the other hand, to-date, compiler optimization have focused on analysis, transformations and performance enhancement of applications in isolation ignoring the problem of optimizing performance for applications as a group. This is because of the infeasibility of global-compiler analysis across applications as well as due to the dynamic nature of inter-application interactions which is statically unknown.