• Priority Inheritance protocols are greedy while Priority Ceiling protocols are not The allocation rule of priority inheritance protocol lets the requesting job have a resource whenever the resource is free but in case of priority ceiling protocol, a job may be denied its requested resource even when the resource is free at the time (J4 at time 3 above)
  • The priority inheritance rules of these two protocols are the same
  • In principle, both rules say that whenever a lower priority job Jl blocks the job J whose request is just denied, the priority of Jl is raised to J‟s priority π(t)
  • The difference arises because of the non-greedy nature of the priority ceiling protocol
  • If is possible for J to be blocked by a lower priority job which does not hold the requested resource according to the priority ceiling protocol while this is impossible according to the priority inheritance protocol.
  • The set of priority ceiling of resources impose a linear order on all the resources, so deadlock can never occur under priority ceiling protocol.
  • The priority celling protocol gives the good performance but defining rules are complex.
  • Priority celling protocol falls under high contexts with overhead due to frequent switching as compared with inheritance protocol.