app/test: improve accuracy on hash measurements

Cycles per hash calculation were measured per single operation.
It is much more accurate to run several iterations between measurements
and divide by number of iterations.

Signed-off-by: Pablo de Lara <pablo.de.lara.guarch@intel.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>

diff --git a/app/test/test_hash_functions.c b/app/test/test_hash_functions.c
index 4efb3cd..767b2bc 100644 (file)
--- a/app/test/test_hash_functions.c
+++ b/app/test/test_hash_functions.c
@@ -83,21 +83,21 @@ static void
 run_hash_func_perf_test(rte_hash_function f, uint32_t init_val,
                uint32_t key_len)
 {
-       static uint8_t key[RTE_HASH_KEY_LENGTH_MAX];
-       uint64_t ticks = 0, start, end;
+       static uint8_t key[HASHTEST_ITERATIONS][RTE_HASH_KEY_LENGTH_MAX];
+       uint64_t ticks, start, end;
        unsigned i, j;
 
        for (i = 0; i < HASHTEST_ITERATIONS; i++) {
-
                for (j = 0; j < key_len; j++)
-                       key[j] = (uint8_t) rte_rand();
-
-               start = rte_rdtsc();
-               f(key, key_len, init_val);
-               end = rte_rdtsc();
-               ticks += end - start;
+                       key[i][j] = (uint8_t) rte_rand();
        }
 
+       start = rte_rdtsc();
+       for (i = 0; i < HASHTEST_ITERATIONS; i++)
+               f(key[i], key_len, init_val);
+       end = rte_rdtsc();
+       ticks = end - start;
+
        printf("%-12s, %-18u, %-13u, %.02f\n", get_hash_name(f), (unsigned) key_len,
                        (unsigned) init_val, (double)ticks / HASHTEST_ITERATIONS);
 }