GPU Pro 5

466 VI Compute

more than twice as fast as the estimate. Because ALU operation time cannot

be shortened, the only reason for superior performance is that the two-level con-

straint solver has faster memory access. This is possible only because of better

utilization of the cache hierarchy.

Cache utilization is low for the global constraint solver because a rigid body is

processed only once in a kernel and the assignment of a constraint to a SIMD is

random for each kernel. Therefore, it cannot reuse any cached data from previous

kernel executions. In contrast, localized constraint solving and in-SIMD batch

dispatch of the two-level solver enable it to