DYON: Managing a New Scheduling Class to Improve System Performance in Multicore Systems

Due to the increase in the number of available cores in current systems, plenty of system software starts to use some of these cores to perform tasks that will help optimize the application behaviour. Unfortunately, current Onload mechanisms are too limited. On the one hand, there is no dynamic way to decide the number of cores that is taken from applications and given to these system helpers. And, on the other hand, the onload mechanisms do not offer enough control over when and where onloading tasks should to be executed. In this paper we propose a new Onload Framework that addresses these issues. First, we propose DYON, a dynamic and adaptive method to control the amount of extra CPUs offered to the Onload Framework to generate benefits for the whole system. And second, we propose a submission mechanism that given a task, executes it if there are idle resources or rejects it otherwise. This feature is useful to move the execution of small pieces of code out of the critical path (allowing parallel execution) when this is possible, or discard them and execute a code that will not rely on them.