Cache Conscious Programming

• Arrays are row-major in C
• Consider an arr[i][j] type of 2D array...
• Then for (j=0;j<N;j++) for (i=0;i<M;i++) will be much slower than for (i=0;i<N;i++) for (j=0;j<M;j++) due to the way of caching
• Metrics show that it can be up to 35x slower