=== pachi-0001: Defect: node->is_expanded acquired with __sync_lock_test_and_set() (atomic test-and-set) ===
N=100   k=100  : defective=0.097ms  fixed=0.004ms  speedup=24.7x
N=500   k=500  : defective=2.432ms  fixed=0.023ms  speedup=106.9x
N=1000  k=1000 : defective=11.798ms  fixed=0.052ms  speedup=227.0x
N=2000  k=2000 : defective=41.603ms  fixed=0.099ms  speedup=418.9x

