quakeforge/libs/util/test/test-ringbuffer.c
Bill Currie 2a47a61bc3 [util] Add atomic ring buffer and automated tests
Just head and tail are atomic, but it seems to work nicely (at least on
intel). I actually had more trouble with gcc (due to accidentally
testing lock-free with the wrong ring buffer... oops, but yup, gcc will
happily optimize your loop to spin really really fast). Also served as a
nice test for C11 threading.
2022-09-22 09:35:57 +09:00

313 lines
6.6 KiB
C

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <threads.h>
#include "QF/dstring.h"
#include "QF/mathlib.h"
#include "QF/ringbuffer.h"
#include "QF/sys.h"
typedef int (*test_func) (int a, int b);
typedef RING_BUFFER (int, 8) ringbuffer_t;
typedef RING_BUFFER (char, 8) ringbuffer_char_t;
typedef RING_BUFFER_ATOMIC (char, 8) ringbuffer_atomic_t;
static ringbuffer_t int_ringbuffer = { .buffer = { [0 ... 7] = 0xdeadbeef } };
static ringbuffer_char_t ringbuffer_char;
static ringbuffer_atomic_t ringbuffer_atomic;
mtx_t rb_mtx;
cnd_t rb_write_cnd;
cnd_t rb_read_cnd;
ringbuffer_atomic_t int_ringbuffer_atomic;
static int
get_size (int a, int b)
{
return RB_buffer_size (&int_ringbuffer);
}
static int
space_available (int a, int b)
{
return RB_SPACE_AVAILABLE (int_ringbuffer);
}
static int
data_available (int a, int b)
{
return RB_DATA_AVAILABLE (int_ringbuffer);
}
static int
write_data (int value, int b)
{
return RB_WRITE_DATA (int_ringbuffer, &value, 1);
}
static int
acquire (int count, int b)
{
return *RB_ACQUIRE (int_ringbuffer, count);
}
static int
read_data (int a, int b)
{
int ret;
RB_READ_DATA (int_ringbuffer, &ret, 1);
return ret;
}
static int
release (int count, int b)
{
return RB_RELEASE (int_ringbuffer, count);
}
static int
peek_data (int offset, int b)
{
return *RB_PEEK_DATA (int_ringbuffer, offset);
}
static int
poke_data (int offset, int value)
{
return RB_POKE_DATA (int_ringbuffer, offset, value);
}
static int
init_threading (int a, int b)
{
if (mtx_init (&rb_mtx, mtx_plain) != thrd_success) {
return -1;
}
if (cnd_init (&rb_write_cnd) != thrd_success) {
return -1;
}
if (cnd_init (&rb_read_cnd) != thrd_success) {
return -1;
}
return 0;
}
static const char *text = "Sometimes, it is necessary to write long gibberish "
"in order to test things. Hopefully, this may be an exception, though it's "
"not exactly the most useful or intersting text around.";
static dstring_t *out_text;
static int
compare_strings (int a, int b)
{
int ret = strcmp (out_text->str, text);
dstring_delete (out_text);
out_text = 0;
return ret;
}
static int
locked_reader (void *data)
{
if (!out_text) {
out_text = dstring_new ();
}
dstring_clear (out_text);
do {
mtx_lock (&rb_mtx);
while (RB_DATA_AVAILABLE (ringbuffer_char) < 1) {
cnd_wait (&rb_read_cnd, &rb_mtx);
}
unsigned len = RB_DATA_AVAILABLE (ringbuffer_char);
RB_READ_DATA (ringbuffer_char, dstring_reserve (out_text, len), len);
cnd_signal (&rb_write_cnd);
mtx_unlock (&rb_mtx);
} while (out_text->str[out_text->size - 1]);
return 0;
}
static int
locked_writer (void *data)
{
size_t data_len = strlen (text) + 1; // send nul terminator too
const char *str = text;
while (data_len > 0) {
mtx_lock (&rb_mtx);
while (RB_SPACE_AVAILABLE (ringbuffer_char) < 1) {
cnd_wait (&rb_write_cnd, &rb_mtx);
}
unsigned len = RB_SPACE_AVAILABLE (ringbuffer_char);
len = min (len, data_len);
RB_WRITE_DATA (ringbuffer_char, str, len);
str += len;
data_len -= len;
cnd_signal (&rb_read_cnd);
mtx_unlock (&rb_mtx);
}
return 0;
}
static int
run_locked (int a, int b)
{
thrd_t writer;
thrd_t reader;
if (thrd_create (&writer, locked_writer, 0) != thrd_success) {
return -1;
}
if (thrd_create (&reader, locked_reader, 0) != thrd_success) {
return -1;
}
int res;
if (thrd_join (writer, &res) != thrd_success) {
return -1;
}
if (thrd_join (reader, &res) != thrd_success) {
return -1;
}
return 0;
}
static int
free_reader (void *data)
{
if (!out_text) {
out_text = dstring_new ();
}
dstring_clear (out_text);
do {
while (RB_DATA_AVAILABLE (ringbuffer_atomic) < 1) {
}
unsigned len = RB_DATA_AVAILABLE (ringbuffer_atomic);
RB_READ_DATA (ringbuffer_atomic, dstring_reserve (out_text, len), len);
} while (out_text->str[out_text->size - 1]);
return 0;
}
static int
free_writer (void *data)
{
size_t data_len = strlen (text) + 1; // send nul terminator too
const char *str = text;
while (data_len > 0) {
while (RB_SPACE_AVAILABLE (ringbuffer_atomic) < 1) {
}
unsigned len = RB_SPACE_AVAILABLE (ringbuffer_atomic);
len = min (len, data_len);
RB_WRITE_DATA (ringbuffer_atomic, str, len);
str += len;
data_len -= len;
}
return 0;
}
static int
run_free (int a, int b)
{
thrd_t writer;
thrd_t reader;
if (thrd_create (&writer, free_writer, 0) != thrd_success) {
return -1;
}
if (thrd_create (&reader, free_reader, 0) != thrd_success) {
return -1;
}
int res;
if (thrd_join (writer, &res) != thrd_success) {
return -1;
}
if (thrd_join (reader, &res) != thrd_success) {
return -1;
}
return 0;
}
#define _ 0 // unused parameter
struct {
test_func test;
int param1, param2;
int test_expect;
} tests[] = {
{ get_size, _, _, 8 },
{ space_available, _, _, 7 },
{ data_available, _, _, 0 },
{ write_data, 0x600dc0de, _, 1 },
{ space_available, _, _, 6 },
{ data_available, _, _, 1 },
{ acquire, 0, _, 0xdeadbeef }, // iffy test: 0 count
{ space_available, _, _, 6 },
{ data_available, _, _, 1 },
{ read_data, 1, _, 0x600dc0de },
{ space_available, _, _, 7 },
{ data_available, _, _, 0 },
{ release, 0, _, 1 },
{ space_available, _, _, 7 },
{ data_available, _, _, 0 },
{ poke_data, 0, 1, 1 },
{ poke_data, 1, 2, 2 },
{ poke_data, 2, 3, 3 },
{ poke_data, 3, 4, 4 },
{ poke_data, 4, 5, 5 },
{ poke_data, 5, 6, 6 },
{ acquire, 6, _, 1 },
{ space_available, _, _, 1 },
{ data_available, _, _, 6 },
{ write_data, 7, _, 0 }, // head wrapped to 0
{ space_available, _, _, 0 },
{ data_available, _, _, 7 },
{ peek_data, 0, _, 1 },
{ peek_data, 1, _, 2 },
{ peek_data, 2, _, 3 },
{ peek_data, 3, _, 4 },
{ peek_data, 4, _, 5 },
{ peek_data, 5, _, 6 },
{ peek_data, 6, _, 7 },
{ space_available, _, _, 0 },
{ data_available, _, _, 7 },
{ init_threading, _, _, 0 },
{ run_locked, _, _, 0 },
{ compare_strings, _, _, 0 },
{ run_free, _, _, 0 },
{ compare_strings, _, _, 0 },
};
#define num_tests (sizeof (tests) / sizeof (tests[0]))
int test_start_line = __LINE__ - num_tests - 2;
int
main (int argc, const char **argv)
{
int res = 0;
for (size_t i = 0; i < num_tests; i++) {
int test_res;
test_res = tests[i].test (tests[i].param1, tests[i].param2);
if (test_res != tests[i].test_expect) {
res |= 1;
printf ("test %zd (line %zd) failed\n", i, i + test_start_line);
printf ("expect: %d\n", tests[i].test_expect);
printf ("got : %d\n", test_res);
}
}
return res;
}