Optimization_1x4_8 - Guanmoyu/how-to-optimize-gemm GitHub Wiki

Copy the contents of file MMult_1x4_7.c into a file named MMult_1x4_8.c and change the contents.

Change the first lines in the makefile to

OLD  := MMult_1x4_7
NEW  := MMult_1x4_8     

• make run

octave:3> PlotAll        % this will create the plot

This time the performance graph will look something like

We now unrolled the loop by four. Interestingly enough, this decreases performance slightly. What this probably means is that by adding the optimization, we confused the compiler, which therefore could not do an optimization that it did before.