diff --git a/OpenMP/linear-algebra/kernels/atax/Makefile b/OpenMP/linear-algebra/kernels/atax/Makefile
index 5bc1770..2f81c8c 100644
--- a/OpenMP/linear-algebra/kernels/atax/Makefile
+++ b/OpenMP/linear-algebra/kernels/atax/Makefile
@@ -1,3 +1,10 @@
 -include ../../../utilities/options.mk
 -include ../../../utilities/c2.mk
 
+# Do not use EXTRALARGE_DATASET, int will overflow
+# -DLARGE_DATASET increases the size of arrays, making everything easier to profile
+# -fopenmp enables OpenMP
+# -Wall and -Wextra enable more warnings
+# -O3 applies all compiler optimization, improving from 800ms to 300ms
+# -g3 enables some useful debug things
+CFLAGS= -DLARGE_DATASET -fopenmp -Wall -Wextra -O3 -g3