Clock mesh

Clock mesh. Instead of a tree, the clock wires are shorted into a mesh and the clock is injected at a few driver points. The clock load is not uniform: the background heat map shows where it is heavy (red) - regions dense with switching flip-flops droop badly unless a driver sits close, while cool regions tolerate being far from one.

• Worst droop under target - each node's skew is its clock load times its distance to the nearest driver. Click mesh nodes to inject drivers, and concentrate them on the hot regions so their distance there is small. A node's ring turns red when its droop is over the limit.
• Drivers within the power budget - every driver burns power, so cover the load with the fewest drivers you can.

The lesson is that the heavy regions need drivers packed in close while the light regions can be sparse. A mesh buys low skew and robustness at the cost of clock power. Place the drivers where the load is, then Submit design.