The present invention extends to methods, systems, and computer program products for using pulses to control work ingress. Generally, embodiments of the invention use a variable-speed clock for accepting work for lower-priority services. A clock rate is controlled by a load monitor. The load monitor periodically collects sensor measurements of resources available after allocations by higher-priority services. Based on the sensor measurements, the load monitor adjusts the clock speed up or down (i.e., depending on the amount of resources available after allocations by higher-priority services). At the boundary of the lower-priority service (e.g., where work enters the system), work requests are enqueued to be associated with a future pulse of the clock. Work is accepted or rejected based on a determination of whether the work request can be allocated a clock pulse within a defined period of time.