Add C benchmark for vlen buffer management (#304)

tests/perf/arrayperf/bytes_to_vlen.c

@@ -0,0 +1,274 @@
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <math.h>
+#include <stdint.h>
+#include <time.h>
+
+#define ASSERT_NOT_EQUAL(ret, val, where)                                                                               \
+    do {                                                                                                     \
+        if ((ret) == (val)) {                                                                                \
+          long _ret = (long) ret, _val = (long) val;\
+          printf("Unexpected return at %s: %ld == %ld\n",  where, _ret, _val);\
+          exit(1);\
+        }                                                                                                    \
+    } while (0)
+
+#define ASSERT_EQUAL(_x, _val, where)                                                                              \
+    do {                                                                                                     \
+        long __x = (long)_x, __val = (long)_val;                                                             \
+        if ((__x) != (__val)) {                                                                              \
+            printf("Unexpected return at %s: %ld != %ld\n", where, __x, __val);\
+                      exit(1);\
+        }                                                                                                    \
+    } while (0)
+
+#define ASSERT_TRUE(b) \
+    do {\
+        if (!(b)) {\
+            printf("Assertion failed");\
+            exit(1);\
+        }\
+    } while (0)
+
+#define RAND_INT(min, max) (rand() % (max - min + 1) + min)
+
+#define MAX_LEN 100
+#define LOWERCASE_A_ASCII 97
+#define LOWERCASE_Z_ASCII 122
+#define FAIL -1
+
+/* Number of bytes used to store size of each string */
+#define NUM_SIZE_BYTES 4
+
+/* Serialize an array of N pointers to variable-length strings to a byte array. */
+char* array_to_bytes(const char** arr_in, size_t num_strings, size_t *lengths);
+
+/*  Deserialize an array of bytes to an array of pointers to variable-length strings. */
+char **bytes_to_array(char *bytes_in, size_t num_strings);
+
+/* Generate num_strings strings, where the i-th string has size lengths[i]. */
+char **generate_random_strings(size_t num_strings, size_t *lengths);
+
+/* Show strings in the array for debugging */
+void display_strings(char **strings, size_t num_strings);
+
+/* Compute elapsed time in seconds from two timespecs */
+double get_elapsed(struct timespec start, struct timespec end);
+
+/* Time serialization and deserialization of a buffer of pointers to variable length strings
+
+Example output:
+
+$ ./bytesToVlen 10000
+Total amount of data = 507511 bytes
+array_to_bytes took 0.000248 seconds for 10000 elements (2043037719 bytes/sec)
+array_to_bytes took 0.000353 seconds for 10000 elements (1438368316 bytes/sec)
+Serialization and deserialization values are correct
+Benchmark complete
+*/
+int main(int argc, char *argv[]) {
+    size_t num_strings = 0;
+    size_t total_size = 0;
+
+    size_t *str_lengths = NULL;
+    char **strings_arr = NULL;
+    char **deserialized_strings_arr = NULL;
+
+    char *serialized_bytes = NULL;
+    char *bytes_ptr = NULL;
+
+    double elapsed = 0.0;
+    struct timespec start;
+    struct timespec end;
+
+    /* Parse commmand line arguments */
+    if (argc != 2) {
+        printf("usage: ./vlenBenchmark count\n");
+        exit(1);
+    }
+
+    if ((num_strings = strtol(argv[1], NULL, 10)) == 0) {
+        printf("count must be greater than 0\n");
+        exit(1);
+    }
+
+    /* Allocate memory for lengths */
+    str_lengths = calloc(num_strings, sizeof(size_t));
+
+    /* Generate strings to serialize and deserialize */
+    strings_arr = generate_random_strings(num_strings, str_lengths);
+
+    for (size_t i = 0; i < num_strings; i++) {
+        total_size += str_lengths[i];
+    }
+
+    printf("Total amount of data = %zu bytes\n", total_size);
+
+    /* Time serialization to bytes */
+    ASSERT_NOT_EQUAL(clock_gettime(CLOCK_MONOTONIC, &start), FAIL, "clock_gettime");
+
+    serialized_bytes = array_to_bytes((const char **) strings_arr, num_strings, str_lengths);
+
+    ASSERT_NOT_EQUAL(clock_gettime(CLOCK_MONOTONIC, &end), FAIL, "clock_gettime");
+
+    elapsed = get_elapsed(start, end);
+
+    printf("array_to_bytes took %lf seconds for %zu elements (%zu bytes/sec)\n", elapsed, num_strings, (size_t) ((double) total_size / elapsed));
+
+    /* Time deserialization back to array of pointers */
+    ASSERT_NOT_EQUAL(clock_gettime(CLOCK_MONOTONIC, &start), FAIL, "clock_gettime");
+
+    deserialized_strings_arr = bytes_to_array(serialized_bytes, num_strings);
+
+    ASSERT_NOT_EQUAL(clock_gettime(CLOCK_MONOTONIC, &end), FAIL, "clock_gettime");
+
+    elapsed = get_elapsed(start, end);
+
+    printf("bytes_to_array took %lf seconds for %zu elements (%zu bytes/sec)\n", elapsed, num_strings, (size_t) ((double) total_size / elapsed));
+
+    /* Check Correctness */
+    for (size_t i = 0; i < num_strings; i++) {
+        ASSERT_TRUE(!strcmp(strings_arr[i], deserialized_strings_arr[i]));
+        ASSERT_EQUAL(str_lengths[i], strlen(deserialized_strings_arr[i]) + 1, "string size check");
+    }
+
+    printf("Serialization and deserialization values are correct\n");
+
+    /* Clean up */
+    if (strings_arr) {
+        for (size_t i = 0; i < num_strings; i++) {
+            if (strings_arr[i]) {
+                free(strings_arr[i]);
+            }
+        }
+
+        free(strings_arr);
+    }
+
+    if (deserialized_strings_arr) {
+        for (size_t i = 0; i < num_strings; i++) {
+            if (deserialized_strings_arr[i]) {
+                free(deserialized_strings_arr[i]);
+            }
+        }
+
+        free(deserialized_strings_arr);
+    }
+
+    if (serialized_bytes) {
+        free(serialized_bytes);
+    }
+
+    if (str_lengths) {
+        free(str_lengths);
+    }
+
+    printf("Benchmark complete\n");
+}
+
+/* Serialize an array of N pointers to variable-length strings to a byte array.
+   Each element is NUM_SIZE_BYTES bytes to describe the size of the string, then the string itself.
+*/
+char* array_to_bytes(const char** arr_in, size_t num_strings, size_t *lengths) {
+    size_t total_size = 0;
+    char *bytes_out = NULL;
+    char *bytes_ptr = NULL;
+
+    /* Determine size and allocate memory */
+    total_size += NUM_SIZE_BYTES * num_strings;
+    for (size_t i = 0; i < num_strings; i++) {
+        total_size += lengths[i];
+    }
+
+    bytes_out = malloc(total_size);
+    bytes_ptr = bytes_out;
+
+    /* Serialize each element */
+    for (size_t i = 0; i < num_strings; i++) {
+        /* Write size */
+        /* Cast size_t to uint32_t to only copy lower bits */
+        memcpy(bytes_ptr, (uint32_t*) &lengths[i], NUM_SIZE_BYTES);
+        bytes_ptr += NUM_SIZE_BYTES;
+
+        /* Write string */
+        memcpy(bytes_ptr, arr_in[i], lengths[i]);
+        bytes_ptr += lengths[i];
+    }
+
+    return bytes_out;
+}
+
+/*  Deserialize an array of bytes to an array of pointers to variable-length strings. 
+    The strings are serialized as described in array_to_bytes
+*/
+char **bytes_to_array(char *bytes_in, size_t num_strings) {
+    char *bytes_ptr = bytes_in;
+    char **strings_out = NULL;
+
+    strings_out = calloc(num_strings, sizeof(char*));
+
+    for (size_t i = 0; i < num_strings; i++) {
+        char curr_string[MAX_LEN];
+        size_t curr_size = 0;
+
+        /* Read size of string */
+        curr_size = (size_t) *((uint32_t*) bytes_ptr);
+        bytes_ptr += NUM_SIZE_BYTES;
+
+        strings_out[i] = malloc(curr_size);
+        /* Read string value */
+        memcpy(strings_out[i], bytes_ptr, curr_size);
+        bytes_ptr += curr_size;
+    }
+
+    return strings_out;
+}
+
+/* Generate num_strings strings, where the i-th string has size lengths[i]. */
+char **generate_random_strings(size_t num_strings, size_t *lengths) {
+    /* Generate num_strings lengths between 1 and max_len inclusive */
+    ASSERT_NOT_EQUAL(lengths, NULL, "lengths arg to generate random strings");
+
+    char **strings_out = NULL;
+
+    for (size_t i = 0; i < num_strings; i++) {
+        lengths[i] = RAND_INT(1, MAX_LEN);
+    }
+
+    /* Allocate memory for strings */
+    strings_out = calloc(num_strings, sizeof(char*));
+
+    for (size_t i = 0; i < num_strings; i++) {
+        strings_out[i] = malloc(lengths[i]);
+    }
+
+    /* Populate string buffers */
+    for (size_t i = 0; i < num_strings; i++) {
+        for (size_t c_idx = 0; c_idx < lengths[i] - 1; c_idx++) {
+            char random_char = (char) RAND_INT(LOWERCASE_A_ASCII, LOWERCASE_Z_ASCII);
+            strings_out[i][c_idx] = random_char;
+        }
+
+        strings_out[i][lengths[i] - 1] = '\0';
+    }
+
+    return strings_out;
+}
+
+/* Show strings in the array for debugging */
+void display_strings(char **strings, size_t num_strings) {
+    for (size_t i = 0; i < num_strings; i++) {
+        printf("String #%zu: %s\n", i, strings[i]);
+    }
+}
+
+/* Compute elapsed time in seconds from two timespecs */
+double get_elapsed(struct timespec start, struct timespec end) {
+    double out = 0.0;
+
+    out += (end.tv_sec - start.tv_sec);
+    out += (end.tv_nsec - start.tv_nsec) / pow(10.0, 9);
+
+    return out;
+}