diff --git a/tools/testing/selftests/resctrl/cache.c b/tools/testing/selftests/resctrl/cache.c
index 1ff1104e6575..bef71b6feacc 100644
--- a/tools/testing/selftests/resctrl/cache.c
+++ b/tools/testing/selftests/resctrl/cache.c
@@ -173,6 +173,19 @@ int measure_llc_resctrl(const char *filename, pid_t bm_pid)
 	return print_results_cache(filename, bm_pid, llc_occu_resc);
 }
 
+/*
+ * Reduce L2 allocation to minimum when testing L3 cache allocation.
+ */
+int minimize_l2_occupancy(const struct resctrl_test *test,
+			  const struct user_params *uparams,
+			  const struct resctrl_val_param *param)
+{
+	if (!strcmp(test->resource, "L3") && resctrl_resource_exists("L2"))
+		return write_schemata(param->ctrlgrp, "0x1", uparams->cpu, "L2");
+
+	return 0;
+}
+
 /*
  * show_cache_info - Show generic cache test information
  * @no_of_bits:		Number of bits
diff --git a/tools/testing/selftests/resctrl/cmt_test.c b/tools/testing/selftests/resctrl/cmt_test.c
index 7bc6cf49c1c5..ccb6fe881a94 100644
--- a/tools/testing/selftests/resctrl/cmt_test.c
+++ b/tools/testing/selftests/resctrl/cmt_test.c
@@ -23,7 +23,9 @@
  * Initialize capacity bitmasks (CBMs) of:
  * - control group being tested per test parameters,
  * - default resource group as inverse of control group being tested to prevent
- *   other tasks from interfering with test.
+ *   other tasks from interfering with test,
+ * - L2 resource of control group being tested to minimize allocations into
+ *   L2 if possible to better predict L3 occupancy.
  */
 static int cmt_init(const struct resctrl_test *test,
 		    const struct user_params *uparams,
@@ -46,7 +48,11 @@ static int cmt_init(const struct resctrl_test *test,
 		return ret;
 
 	snprintf(schemata, sizeof(schemata), "%lx", param->mask);
-	return write_schemata(param->ctrlgrp, schemata, uparams->cpu, test->resource);
+	ret = write_schemata(param->ctrlgrp, schemata, uparams->cpu, test->resource);
+	if (ret)
+		return ret;
+
+	return minimize_l2_occupancy(test, uparams, param);
 }
 
 static int cmt_setup(const struct resctrl_test *test,
@@ -175,11 +181,11 @@ static int cmt_run_test(const struct resctrl_test *test, const struct user_param
 	span = cache_portion_size(cache_total_size, param.mask, long_mask);
 
 	if (uparams->fill_buf) {
-		fill_buf.buf_size = span;
+		fill_buf.buf_size = span * 2;
 		fill_buf.memflush = uparams->fill_buf->memflush;
 		param.fill_buf = &fill_buf;
 	} else if (!uparams->benchmark_cmd[0]) {
-		fill_buf.buf_size = span;
+		fill_buf.buf_size = span * 2;
 		fill_buf.memflush = true;
 		param.fill_buf = &fill_buf;
 	}
diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h
index c72045c74ac4..7f2ab28be857 100644
--- a/tools/testing/selftests/resctrl/resctrl.h
+++ b/tools/testing/selftests/resctrl/resctrl.h
@@ -216,6 +216,9 @@ int perf_event_reset_enable(int pe_fd);
 int perf_event_measure(int pe_fd, struct perf_event_read *pe_read,
 		       const char *filename, pid_t bm_pid);
 int measure_llc_resctrl(const char *filename, pid_t bm_pid);
+int minimize_l2_occupancy(const struct resctrl_test *test,
+			  const struct user_params *uparams,
+			  const struct resctrl_val_param *param);
 void show_cache_info(int no_of_bits, __u64 avg_llc_val, size_t cache_span, bool lines);
 
 /*