Abstract
Scheduling and timer interrupt extends PQEMU SCC to execute and supports to emulate 255 VCPUs on x86 platform. This paper strongly emphasizes while we emu-late 255 VCPUs, what problems we face. These problems lead to operating system lite then slow heavy then crash. Therefore, we can know the significance of these problem, these problems are caused by context switching, host scheduler and timing problem. Nonetheless, this paper provides two methods of solving these problems which are group scheduling and mask timer interrupt, group scheduling want to solve the prob-lem which is the overhead of context switch or host scheduler. Moreover, we want to decrease mask timer interrupt to solve the problem which is accumulative timer inter-rupts because time interval of tick is fix but we emulate number of VCPUs larger than physical CPU so that we have small time slice to execute every VCPU, we enlarge time interval of tick by using mask timer interrupt. Above all, we implement group scheduling and mask timer interrupt so that we can emulate 255 VCPUs, despite of emulating 255 VCPUs, it just need few minute to start up.