Update level3.c

driver/level3/level3.c

@@ -332,13 +332,16 @@ int CNAME(blas_arg_t *args, BLASLONG *range_m, BLASLONG *range_n,
 #else
       for(jjs = js; jjs < js + min_j; jjs += min_jj){
 	min_jj = min_j + js - jjs;
-
+#ifdef SKYLAKEX
+	/* the current AVX512 s/d/c/z GEMM kernel requires n>=6*GEMM_UNROLL_N to achieve best performance */
+	if (min_jj >= 6*GEMM_UNROLL_N) min_jj = 6*GEMM_UNROLL_N;
+#else
         if (min_jj >= 3*GEMM_UNROLL_N) min_jj = 3*GEMM_UNROLL_N;
         else
         	if (min_jj >= 2*GEMM_UNROLL_N) min_jj = 2*GEMM_UNROLL_N;
         	else
           		if (min_jj > GEMM_UNROLL_N) min_jj = GEMM_UNROLL_N;
-
+#endif
 
 
 	START_RPCC();