[ECS EC2] [request] How to specify vCPU reservation with hard limit together?

I run about 30 tasks that host 1 container, I'm using EC2.

I need to limit resources for the containers.

For memory, I use `taskDefinition.containerDefinitions[0].memory = 512` and `taskDefinition.containerDefinitions[0].memoryReservation = 265` to make possible to run more containers but still limiting each individual container up to `512M`, because the real consumption too often is low.

For CPU I have to use `taskDefinition.cpu = '.5 vCPU'` (task size) parameter to limit each individual container up to 50% of 1 vCPU. But like for the memory, I want to reserve less CPU capacity, because the actual usage is less than 10% very often.

How I can reserve less vCPU (for example `256 vCPU`) but still limit the container to use up to `512 vCPU`?