[dpdk-dev] [PATCH v8 3/3] test: add tests for reciprocal based division

[Pavan Nikhilesh]

This commit provides a set of tests for verifying the correctness and
performance of both unsigned 32 and 64bit reciprocal based division.

Signed-off-by: Pavan Nikhilesh <pbhagavatula at caviumnetworks.com>
---
 test/test/Makefile                        |   2 +
 test/test/test_reciprocal_division.c      | 167 +++++++++++++++++++++++++
 test/test/test_reciprocal_division_perf.c | 201 ++++++++++++++++++++++++++++++
 3 files changed, 370 insertions(+)
 create mode 100644 test/test/test_reciprocal_division.c
 create mode 100644 test/test/test_reciprocal_division_perf.c

diff --git a/test/test/Makefile b/test/test/Makefile
index 5ba5a9ac7..c943a927a 100644
--- a/test/test/Makefile
+++ b/test/test/Makefile
@@ -67,6 +67,8 @@ SRCS-y += test_spinlock.c
 SRCS-y += test_memory.c
 SRCS-y += test_memzone.c
 SRCS-y += test_bitmap.c
+SRCS-y += test_reciprocal_division.c
+SRCS-y += test_reciprocal_division_perf.c
 
 SRCS-y += test_ring.c
 SRCS-y += test_ring_perf.c
diff --git a/test/test/test_reciprocal_division.c b/test/test/test_reciprocal_division.c
new file mode 100644
index 000000000..8ea9b1d24
--- /dev/null
+++ b/test/test/test_reciprocal_division.c
@@ -0,0 +1,167 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2017 Cavium, Inc
+ */
+
+#include "test.h"
+
+#include <stdio.h>
+#include <unistd.h>
+#include <inttypes.h>
+
+#include <rte_common.h>
+#include <rte_cycles.h>
+#include <rte_random.h>
+#include <rte_reciprocal.h>
+
+#define MAX_ITERATIONS	(1ULL << 32)
+#define DIVIDE_ITER	(100)
+
+static int
+test_reciprocal(void)
+{
+	int result = 0;
+	uint32_t divisor_u32 = 0;
+	uint32_t dividend_u32;
+	uint32_t nresult_u32;
+	uint32_t rresult_u32;
+	uint64_t i, j;
+	uint64_t divisor_u64 = 0;
+	uint64_t dividend_u64;
+	uint64_t nresult_u64;
+	uint64_t rresult_u64;
+	struct rte_reciprocal reci_u32 = {0};
+	struct rte_reciprocal_u64 reci_u64 = {0};
+
+	rte_srand(rte_rdtsc());
+	printf("Validating unsigned 32bit division.\n");
+	for (i = 0; i < MAX_ITERATIONS; i++) {
+		/* Change divisor every DIVIDE_ITER iterations. */
+		if (i % DIVIDE_ITER == 0) {
+			divisor_u32 = rte_rand();
+			reci_u32 = rte_reciprocal_value(divisor_u32);
+		}
+
+		dividend_u32 = rte_rand();
+		nresult_u32 = dividend_u32 / divisor_u32;
+		rresult_u32 = rte_reciprocal_divide(dividend_u32,
+				reci_u32);
+		if (nresult_u32 != rresult_u32) {
+			printf("Division failed, %"PRIu32"/%"PRIu32" = "
+					"expected %"PRIu32" result %"PRIu32"\n",
+					dividend_u32, divisor_u32,
+					nresult_u32, rresult_u32);
+			result = 1;
+			break;
+		}
+	}
+
+	printf("Validating unsigned 64bit division.\n");
+	for (i = 0; i < MAX_ITERATIONS; i++) {
+		/* Change divisor every DIVIDE_ITER iterations. */
+		if (i % DIVIDE_ITER == 0) {
+			divisor_u64 = rte_rand();
+			reci_u64 = rte_reciprocal_value_u64(divisor_u64);
+		}
+
+		dividend_u64 = rte_rand();
+		nresult_u64 = dividend_u64 / divisor_u64;
+		rresult_u64 = rte_reciprocal_divide_u64(dividend_u64,
+				&reci_u64);
+		if (nresult_u64 != rresult_u64) {
+			printf("Division failed,  %"PRIu64"/%"PRIu64" = "
+					"expected %"PRIu64" result %"PRIu64"\n",
+					dividend_u64, divisor_u64,
+					nresult_u64, rresult_u64);
+			result = 1;
+			break;
+		}
+	}
+
+	printf("Validating unsigned 64bit division with 32bit divisor.\n");
+	for (i = 0; i < MAX_ITERATIONS; i++) {
+		/* Change divisor every DIVIDE_ITER iterations. */
+		if (i % DIVIDE_ITER == 0) {
+			divisor_u64 = rte_rand() >> 32;
+			reci_u64 = rte_reciprocal_value_u64(divisor_u64);
+		}
+
+		dividend_u64 = rte_rand();
+
+		nresult_u64 = dividend_u64 / divisor_u64;
+		rresult_u64 = rte_reciprocal_divide_u64(dividend_u64,
+				&reci_u64);
+
+		if (nresult_u64 != rresult_u64) {
+			printf("Division failed, %"PRIu64"/%"PRIu64" = "
+					"expected %"PRIu64" result %"PRIu64"\n",
+					dividend_u64, divisor_u64,
+					nresult_u64, rresult_u64);
+			result = 1;
+			break;
+		}
+	}
+
+	printf("Validating division by power of 2.\n");
+	for (i = 0; i < 32; i++) {
+		divisor_u64 = 1ull << i;
+		reci_u64 = rte_reciprocal_value_u64(divisor_u64);
+		reci_u32 = rte_reciprocal_value((uint32_t)divisor_u64);
+
+		for (j = 0; j < MAX_ITERATIONS >> 4; j++) {
+			dividend_u64 = rte_rand();
+
+			nresult_u64 = dividend_u64 / divisor_u64;
+			rresult_u64 = rte_reciprocal_divide_u64(dividend_u64,
+					&reci_u64);
+
+			if (nresult_u64 != rresult_u64) {
+				printf(
+				"Division 64 failed, %"PRIu64"/%"PRIu64" = "
+					"expected %"PRIu64" result %"PRIu64"\n",
+						dividend_u64, divisor_u64,
+						nresult_u64, rresult_u64);
+				result = 1;
+			}
+
+			nresult_u32 = (dividend_u64 >> 32) / divisor_u64;
+			rresult_u32 = rte_reciprocal_divide(
+					(dividend_u64 >> 32), reci_u32);
+
+			if (nresult_u32 != rresult_u32) {
+				printf(
+				"Division 32 failed, %"PRIu64"/%"PRIu64" = "
+					"expected %"PRIu64" result %"PRIu64"\n",
+						dividend_u64 >> 32, divisor_u64,
+						nresult_u64, rresult_u64);
+				result = 1;
+				break;
+			}
+		}
+	}
+
+	for (; i < 64; i++) {
+		divisor_u64 = 1ull << i;
+		reci_u64 = rte_reciprocal_value_u64(divisor_u64);
+
+		for (j = 0; j < MAX_ITERATIONS >> 4; j++) {
+			dividend_u64 = rte_rand();
+
+			nresult_u64 = dividend_u64 / divisor_u64;
+			rresult_u64 = rte_reciprocal_divide_u64(dividend_u64,
+					&reci_u64);
+
+			if (nresult_u64 != rresult_u64) {
+				printf("Division failed, %"PRIu64"/%"PRIu64" = "
+					"expected %"PRIu64" result %"PRIu64"\n",
+						dividend_u64, divisor_u64,
+						nresult_u64, rresult_u64);
+				result = 1;
+				break;
+			}
+		}
+	}
+
+	return result;
+}
+
+REGISTER_TEST_COMMAND(reciprocal_division, test_reciprocal);
diff --git a/test/test/test_reciprocal_division_perf.c b/test/test/test_reciprocal_division_perf.c
new file mode 100644
index 000000000..a7be8aa71
--- /dev/null
+++ b/test/test/test_reciprocal_division_perf.c
@@ -0,0 +1,201 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2017 Cavium, Inc
+ */
+
+#include "test.h"
+
+#include <stdio.h>
+#include <unistd.h>
+#include <inttypes.h>
+
+#include <rte_common.h>
+#include <rte_cycles.h>
+#include <rte_random.h>
+#include <rte_reciprocal.h>
+
+#define MAX_ITERATIONS	(1ULL << 32)
+#define DIVIDE_ITER	(1ULL << 28)
+
+static int
+test_reciprocal_division_perf(void)
+{
+	int result = 0;
+	uint32_t divisor_u32 = 0;
+	uint32_t dividend_u32;
+	uint64_t divisor_u64 = 0;
+	uint64_t dividend_u64;
+	volatile uint32_t nresult_u32;
+	volatile uint32_t rresult_u32;
+	volatile uint64_t nresult_u64;
+	volatile uint64_t rresult_u64;
+	uint64_t start_cyc;
+	uint64_t split_cyc;
+	uint64_t end_cyc;
+	uint64_t tot_cyc_n = 0;
+	uint64_t tot_cyc_r = 0;
+	uint64_t i;
+	struct rte_reciprocal reci_u32 = {0};
+	struct rte_reciprocal_u64 reci_u64 = {0};
+
+	rte_srand(rte_rdtsc());
+
+	printf("Validating unsigned 32bit division.\n");
+	for (i = 0; i < MAX_ITERATIONS; i++) {
+		/* Change divisor every DIVIDE_ITER iterations. */
+		if (i % DIVIDE_ITER == 0) {
+			divisor_u32 = rte_rand();
+			reci_u32 = rte_reciprocal_value(divisor_u32);
+		}
+
+		dividend_u32 = rte_rand();
+
+		start_cyc = rte_rdtsc();
+		nresult_u32 = dividend_u32 / divisor_u32;
+		split_cyc = rte_rdtsc();
+		rresult_u32 = rte_reciprocal_divide(dividend_u32,
+				reci_u32);
+		end_cyc = rte_rdtsc();
+
+		tot_cyc_n += split_cyc - start_cyc;
+		tot_cyc_r += end_cyc - split_cyc;
+		if (nresult_u32 != rresult_u32) {
+			printf("Division failed, expected %"PRIu32" "
+					"result %"PRIu32"",
+					nresult_u32, rresult_u32);
+			result = 1;
+			break;
+		}
+	}
+	printf("32bit Division results:\n");
+	printf("Total number of cycles normal division     : %"PRIu64"\n",
+			tot_cyc_n);
+	printf("Total number of cycles reciprocal division : %"PRIu64"\n",
+			tot_cyc_r);
+	printf("Cycles per division(normal) : %3.2f\n",
+			((double)tot_cyc_n)/i);
+	printf("Cycles per division(reciprocal) : %3.2f\n\n",
+			((double)tot_cyc_r)/i);
+
+	tot_cyc_n = 0;
+	tot_cyc_r = 0;
+
+	printf("Validating unsigned 64bit division.\n");
+	for (i = 0; i < MAX_ITERATIONS; i++) {
+		/* Change divisor every DIVIDE_ITER iterations. */
+		if (i % DIVIDE_ITER == 0) {
+			divisor_u64 = rte_rand();
+			reci_u64 = rte_reciprocal_value_u64(divisor_u64);
+		}
+
+		dividend_u64 = rte_rand();
+
+		start_cyc = rte_rdtsc();
+		nresult_u64 = dividend_u64 / divisor_u64;
+		split_cyc = rte_rdtsc();
+		rresult_u64 = rte_reciprocal_divide_u64(dividend_u64,
+				&reci_u64);
+		end_cyc = rte_rdtsc();
+
+		tot_cyc_n += split_cyc - start_cyc;
+		tot_cyc_r += end_cyc - split_cyc;
+		if (nresult_u64 != rresult_u64) {
+			printf("Division failed, expected %"PRIu64" "
+					"result %"PRIu64"",
+					nresult_u64, rresult_u64);
+			result = 1;
+			break;
+		}
+	}
+	printf("64bit Division results:\n");
+	printf("Total number of cycles normal division     : %"PRIu64"\n",
+			tot_cyc_n);
+	printf("Total number of cycles reciprocal division : %"PRIu64"\n",
+			tot_cyc_r);
+	printf("Cycles per division(normal) : %3.2f\n",
+			((double)tot_cyc_n)/i);
+	printf("Cycles per division(reciprocal) : %3.2f\n\n",
+			((double)tot_cyc_r)/i);
+
+	tot_cyc_n = 0;
+	tot_cyc_r = 0;
+
+	printf("Validating unsigned 64bit division with 32bit divisor.\n");
+	for (i = 0; i < MAX_ITERATIONS; i++) {
+		/* Change divisor every DIVIDE_ITER iterations. */
+		if (i % DIVIDE_ITER == 0) {
+			divisor_u64 = rte_rand() >> 32;
+			reci_u64 = rte_reciprocal_value_u64(divisor_u64);
+		}
+
+		dividend_u64 = rte_rand();
+
+		start_cyc = rte_rdtsc();
+		nresult_u64 = dividend_u64 / divisor_u64;
+		split_cyc = rte_rdtsc();
+		rresult_u64 = rte_reciprocal_divide_u64(dividend_u64,
+				&reci_u64);
+		end_cyc = rte_rdtsc();
+
+		tot_cyc_n += split_cyc - start_cyc;
+		tot_cyc_r += end_cyc - split_cyc;
+		if (nresult_u64 != rresult_u64) {
+			printf("Division failed, expected %"PRIu64" "
+					"result %"PRIu64"",
+					nresult_u64, rresult_u64);
+			result = 1;
+			break;
+		}
+	}
+
+	printf("64bit Division results:\n");
+	printf("Total number of cycles normal division     : %"PRIu64"\n",
+			tot_cyc_n);
+	printf("Total number of cycles reciprocal division : %"PRIu64"\n",
+			tot_cyc_r);
+	printf("Cycles per division(normal) : %3.2f\n",
+			((double)tot_cyc_n)/i);
+	printf("Cycles per division(reciprocal) : %3.2f\n\n",
+			((double)tot_cyc_r)/i);
+
+	tot_cyc_n = 0;
+	tot_cyc_r = 0;
+
+	printf("Validating division by power of 2.\n");
+	for (i = 0; i < 64; i++) {
+		divisor_u64 = 1ull << i;
+		reci_u64 = rte_reciprocal_value_u64(divisor_u64);
+
+		dividend_u64 = rte_rand();
+
+		start_cyc = rte_rdtsc();
+		nresult_u64 = dividend_u64 / divisor_u64;
+		split_cyc = rte_rdtsc();
+		rresult_u64 = rte_reciprocal_divide_u64(dividend_u64,
+				&reci_u64);
+		end_cyc = rte_rdtsc();
+
+		tot_cyc_n += split_cyc - start_cyc;
+		tot_cyc_r += end_cyc - split_cyc;
+		if (nresult_u64 != rresult_u64) {
+			printf("Division 64 failed, %"PRIu64"/%"PRIu64" = "
+					"expected %"PRIu64" result %"PRIu64"\n",
+					dividend_u64, divisor_u64,
+					nresult_u64, rresult_u64);
+			result = 1;
+			break;
+		}
+	}
+	printf("64bit Division results:\n");
+	printf("Total number of cycles normal division     : %"PRIu64"\n",
+			tot_cyc_n);
+	printf("Total number of cycles reciprocal division : %"PRIu64"\n",
+			tot_cyc_r);
+	printf("Cycles per division(normal) : %3.2f\n",
+			((double)tot_cyc_n)/i);
+	printf("Cycles per division(reciprocal) : %3.2f\n",
+			((double)tot_cyc_r)/i);
+
+	return result;
+}
+
+REGISTER_TEST_COMMAND(reciprocal_division_perf, test_reciprocal_division_perf);
-- 
2.14.1