“with contended resources” is the part you are misinterpreting. They are saying that two applications that contend on a resource must cooperate to operate prope

“with contended resources” is the part you are misinterpreting. They are saying that two applications that contend on a resource must cooperate to operate properly. As they clearly state later: “Making everything cooperative increases the analysis needed because the CPU becomes a manually managed contended resource.” i.e. a cooperative scheduler makes all code contend on the CPU, thus requiring global cooperation. Given that they are providing that case as establishing a new requirement (the CPU becomes a contended resource) they are clearly stating in the preemptive scheduler case that the CPU is not a contended resource and thus no global cooperation is required. Only if they contend on a resource do they need cooperation amongst the contending partys. But again, if you are already doing a whole system analysis anyways, then the benefits are less pronounced.