@@ -3,6 +3,10 @@ qht_bench = executable('qht-bench',
sources: 'qht-bench.c',
dependencies: [qemuutil])
+xbzrle_bench = executable('xbzrle-bench',
+ sources: 'xbzrle-bench.c',
+ dependencies: [qemuutil,migration])
+
executable('atomic_add-bench',
sources: files('atomic_add-bench.c'),
dependencies: [qemuutil],
new file mode 100644
@@ -0,0 +1,469 @@
+/*
+ * Xor Based Zero Run Length Encoding unit tests.
+ *
+ * Copyright 2013 Red Hat, Inc. and/or its affiliates
+ *
+ * Authors:
+ * Orit Wasserman <owasserm@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+#include "qemu/osdep.h"
+#include "qemu/cutils.h"
+#include "../migration/xbzrle.h"
+
+#if defined(CONFIG_AVX512BW_OPT)
+#define XBZRLE_PAGE_SIZE 4096
+static bool is_cpu_support_avx512bw;
+#include "qemu/cpuid.h"
+static void __attribute__((constructor)) init_cpu_flag(void)
+{
+ unsigned max = __get_cpuid_max(0, NULL);
+ int a, b, c, d;
+ is_cpu_support_avx512bw = false;
+ if (max >= 1) {
+ __cpuid(1, a, b, c, d);
+ /* We must check that AVX is not just available, but usable. */
+ if ((c & bit_OSXSAVE) && (c & bit_AVX) && max >= 7) {
+ int bv;
+ __asm("xgetbv" : "=a"(bv), "=d"(d) : "c"(0));
+ __cpuid_count(7, 0, a, b, c, d);
+ /* 0xe6:
+ * XCR0[7:5] = 111b (OPMASK state, upper 256-bit of ZMM0-ZMM15
+ * and ZMM16-ZMM31 state are enabled by OS)
+ * XCR0[2:1] = 11b (XMM state and YMM state are enabled by OS)
+ */
+ if ((bv & 0xe6) == 0xe6 && (b & bit_AVX512BW)) {
+ is_cpu_support_avx512bw = true;
+ }
+ }
+ }
+ return ;
+}
+
+struct ResTime {
+ float t_raw;
+ float t_512;
+};
+
+
+/* Function prototypes
+int xbzrle_encode_buffer_avx512(uint8_t *old_buf, uint8_t *new_buf, int slen,
+ uint8_t *dst, int dlen);
+*/
+static void encode_decode_zero(struct ResTime *res)
+{
+ uint8_t *buffer = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *compressed = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *buffer512 = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *compressed512 = g_malloc0(XBZRLE_PAGE_SIZE);
+ int i = 0;
+ int dlen = 0, dlen512 = 0;
+ int diff_len = g_test_rand_int_range(0, XBZRLE_PAGE_SIZE - 1006);
+
+ for (i = diff_len; i > 0; i--) {
+ buffer[1000 + i] = i;
+ buffer512[1000 + i] = i;
+ }
+
+ buffer[1000 + diff_len + 3] = 103;
+ buffer[1000 + diff_len + 5] = 105;
+
+ buffer512[1000 + diff_len + 3] = 103;
+ buffer512[1000 + diff_len + 5] = 105;
+
+ /* encode zero page */
+ time_t t_start, t_end, t_start512, t_end512;
+ t_start = clock();
+ dlen = xbzrle_encode_buffer(buffer, buffer, XBZRLE_PAGE_SIZE, compressed,
+ XBZRLE_PAGE_SIZE);
+ t_end = clock();
+ float time_val = difftime(t_end, t_start);
+ g_assert(dlen == 0);
+
+ t_start512 = clock();
+ dlen512 = xbzrle_encode_buffer_avx512(buffer512, buffer512, XBZRLE_PAGE_SIZE,
+ compressed512, XBZRLE_PAGE_SIZE);
+ t_end512 = clock();
+ float time_val512 = difftime(t_end512, t_start512);
+ g_assert(dlen512 == 0);
+
+ res->t_raw = time_val;
+ res->t_512 = time_val512;
+
+ g_free(buffer);
+ g_free(compressed);
+ g_free(buffer512);
+ g_free(compressed512);
+
+}
+
+static void test_encode_decode_zero_avx512(void)
+{
+ int i;
+ float time_raw = 0.0, time_512 = 0.0;
+ struct ResTime res;
+ for (i = 0; i < 10000; i++) {
+ encode_decode_zero(&res);
+ time_raw += res.t_raw;
+ time_512 += res.t_512;
+ }
+ printf("Zero test:\n");
+ printf("Raw xbzrle_encode time is %f ms\n", time_raw);
+ printf("512 xbzrle_encode time is %f ms\n", time_512);
+}
+
+static void encode_decode_unchanged(struct ResTime *res)
+{
+ uint8_t *compressed = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *test = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *compressed512 = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *test512 = g_malloc0(XBZRLE_PAGE_SIZE);
+ int i = 0;
+ int dlen = 0, dlen512 = 0;
+ int diff_len = g_test_rand_int_range(0, XBZRLE_PAGE_SIZE - 1006);
+
+ for (i = diff_len; i > 0; i--) {
+ test[1000 + i] = i + 4;
+ test512[1000 + i] = i + 4;
+ }
+
+ test[1000 + diff_len + 3] = 107;
+ test[1000 + diff_len + 5] = 109;
+
+ test512[1000 + diff_len + 3] = 107;
+ test512[1000 + diff_len + 5] = 109;
+
+ /* test unchanged buffer */
+ time_t t_start, t_end, t_start512, t_end512;
+ t_start = clock();
+ dlen = xbzrle_encode_buffer(test, test, XBZRLE_PAGE_SIZE, compressed,
+ XBZRLE_PAGE_SIZE);
+ t_end = clock();
+ float time_val = difftime(t_end, t_start);
+ g_assert(dlen == 0);
+
+ t_start512 = clock();
+ dlen512 = xbzrle_encode_buffer_avx512(test512, test512, XBZRLE_PAGE_SIZE,
+ compressed512, XBZRLE_PAGE_SIZE);
+ t_end512 = clock();
+ float time_val512 = difftime(t_end512, t_start512);
+ g_assert(dlen512 == 0);
+
+ res->t_raw = time_val;
+ res->t_512 = time_val512;
+
+ g_free(test);
+ g_free(compressed);
+ g_free(test512);
+ g_free(compressed512);
+
+}
+
+static void test_encode_decode_unchanged_avx512(void)
+{
+ int i;
+ float time_raw = 0.0, time_512 = 0.0;
+ struct ResTime res;
+ for (i = 0; i < 10000; i++) {
+ encode_decode_unchanged(&res);
+ time_raw += res.t_raw;
+ time_512 += res.t_512;
+ }
+ printf("Unchanged test:\n");
+ printf("Raw xbzrle_encode time is %f ms\n", time_raw);
+ printf("512 xbzrle_encode time is %f ms\n", time_512);
+}
+
+static void encode_decode_1_byte(struct ResTime *res)
+{
+ uint8_t *buffer = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *test = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *compressed = g_malloc(XBZRLE_PAGE_SIZE);
+ uint8_t *buffer512 = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *test512 = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *compressed512 = g_malloc(XBZRLE_PAGE_SIZE);
+ int dlen = 0, rc = 0, dlen512 = 0, rc512 = 0;
+ uint8_t buf[2];
+ uint8_t buf512[2];
+
+ test[XBZRLE_PAGE_SIZE - 1] = 1;
+ test512[XBZRLE_PAGE_SIZE - 1] = 1;
+
+ time_t t_start, t_end, t_start512, t_end512;
+ t_start = clock();
+ dlen = xbzrle_encode_buffer(buffer, test, XBZRLE_PAGE_SIZE, compressed,
+ XBZRLE_PAGE_SIZE);
+ t_end = clock();
+ float time_val = difftime(t_end, t_start);
+ g_assert(dlen == (uleb128_encode_small(&buf[0], 4095) + 2));
+
+ rc = xbzrle_decode_buffer(compressed, dlen, buffer, XBZRLE_PAGE_SIZE);
+ g_assert(rc == XBZRLE_PAGE_SIZE);
+ g_assert(memcmp(test, buffer, XBZRLE_PAGE_SIZE) == 0);
+
+ t_start512 = clock();
+ dlen512 = xbzrle_encode_buffer_avx512(buffer512, test512, XBZRLE_PAGE_SIZE,
+ compressed512, XBZRLE_PAGE_SIZE);
+ t_end512 = clock();
+ float time_val512 = difftime(t_end512, t_start512);
+ g_assert(dlen512 == (uleb128_encode_small(&buf512[0], 4095) + 2));
+
+ rc512 = xbzrle_decode_buffer(compressed512, dlen512, buffer512,
+ XBZRLE_PAGE_SIZE);
+ g_assert(rc512 == XBZRLE_PAGE_SIZE);
+ g_assert(memcmp(test512, buffer512, XBZRLE_PAGE_SIZE) == 0);
+
+ res->t_raw = time_val;
+ res->t_512 = time_val512;
+
+ g_free(buffer);
+ g_free(compressed);
+ g_free(test);
+ g_free(buffer512);
+ g_free(compressed512);
+ g_free(test512);
+
+}
+
+static void test_encode_decode_1_byte_avx512(void)
+{
+ int i;
+ float time_raw = 0.0, time_512 = 0.0;
+ struct ResTime res;
+ for (i = 0; i < 10000; i++) {
+ encode_decode_1_byte(&res);
+ time_raw += res.t_raw;
+ time_512 += res.t_512;
+ }
+ printf("1 byte test:\n");
+ printf("Raw xbzrle_encode time is %f ms\n", time_raw);
+ printf("512 xbzrle_encode time is %f ms\n", time_512);
+}
+
+static void encode_decode_overflow(struct ResTime *res)
+{
+ uint8_t *compressed = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *test = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *buffer = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *compressed512 = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *test512 = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *buffer512 = g_malloc0(XBZRLE_PAGE_SIZE);
+ int i = 0, rc = 0, rc512 = 0;
+
+ for (i = 0; i < XBZRLE_PAGE_SIZE / 2 - 1; i++) {
+ test[i * 2] = 1;
+ test512[i * 2] = 1;
+ }
+
+ /* encode overflow */
+ time_t t_start, t_end, t_start512, t_end512;
+ t_start = clock();
+ rc = xbzrle_encode_buffer(buffer, test, XBZRLE_PAGE_SIZE, compressed,
+ XBZRLE_PAGE_SIZE);
+ t_end = clock();
+ float time_val = difftime(t_end, t_start);
+ g_assert(rc == -1);
+
+ t_start512 = clock();
+ rc512 = xbzrle_encode_buffer_avx512(buffer512, test512, XBZRLE_PAGE_SIZE,
+ compressed512, XBZRLE_PAGE_SIZE);
+ t_end512 = clock();
+ float time_val512 = difftime(t_end512, t_start512);
+ g_assert(rc512 == -1);
+
+ res->t_raw = time_val;
+ res->t_512 = time_val512;
+
+ g_free(buffer);
+ g_free(compressed);
+ g_free(test);
+ g_free(buffer512);
+ g_free(compressed512);
+ g_free(test512);
+
+}
+
+static void test_encode_decode_overflow_avx512(void)
+{
+ int i;
+ float time_raw = 0.0, time_512 = 0.0;
+ struct ResTime res;
+ for (i = 0; i < 10000; i++) {
+ encode_decode_overflow(&res);
+ time_raw += res.t_raw;
+ time_512 += res.t_512;
+ }
+ printf("Overflow test:\n");
+ printf("Raw xbzrle_encode time is %f ms\n", time_raw);
+ printf("512 xbzrle_encode time is %f ms\n", time_512);
+}
+
+static void encode_decode_range_avx512(struct ResTime *res)
+{
+ uint8_t *buffer = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *compressed = g_malloc(XBZRLE_PAGE_SIZE);
+ uint8_t *test = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *buffer512 = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *compressed512 = g_malloc(XBZRLE_PAGE_SIZE);
+ uint8_t *test512 = g_malloc0(XBZRLE_PAGE_SIZE);
+ int i = 0, rc = 0, rc512 = 0;
+ int dlen = 0, dlen512 = 0;
+
+ int diff_len = g_test_rand_int_range(0, XBZRLE_PAGE_SIZE - 1006);
+
+ for (i = diff_len; i > 0; i--) {
+ buffer[1000 + i] = i;
+ test[1000 + i] = i + 4;
+ buffer512[1000 + i] = i;
+ test512[1000 + i] = i + 4;
+ }
+
+ buffer[1000 + diff_len + 3] = 103;
+ test[1000 + diff_len + 3] = 107;
+
+ buffer[1000 + diff_len + 5] = 105;
+ test[1000 + diff_len + 5] = 109;
+
+ buffer512[1000 + diff_len + 3] = 103;
+ test512[1000 + diff_len + 3] = 107;
+
+ buffer512[1000 + diff_len + 5] = 105;
+ test512[1000 + diff_len + 5] = 109;
+
+ /* test encode/decode */
+ time_t t_start, t_end, t_start512, t_end512;
+ t_start = clock();
+ dlen = xbzrle_encode_buffer(test, buffer, XBZRLE_PAGE_SIZE, compressed,
+ XBZRLE_PAGE_SIZE);
+ t_end = clock();
+ float time_val = difftime(t_end, t_start);
+ rc = xbzrle_decode_buffer(compressed, dlen, test, XBZRLE_PAGE_SIZE);
+ g_assert(rc < XBZRLE_PAGE_SIZE);
+ g_assert(memcmp(test, buffer, XBZRLE_PAGE_SIZE) == 0);
+
+ t_start512 = clock();
+ dlen512 = xbzrle_encode_buffer_avx512(test512, buffer512, XBZRLE_PAGE_SIZE,
+ compressed512, XBZRLE_PAGE_SIZE);
+ t_end512 = clock();
+ float time_val512 = difftime(t_end512, t_start512);
+ rc512 = xbzrle_decode_buffer(compressed512, dlen512, test512, XBZRLE_PAGE_SIZE);
+ g_assert(rc512 < XBZRLE_PAGE_SIZE);
+ g_assert(memcmp(test512, buffer512, XBZRLE_PAGE_SIZE) == 0);
+
+ res->t_raw = time_val;
+ res->t_512 = time_val512;
+
+ g_free(buffer);
+ g_free(compressed);
+ g_free(test);
+ g_free(buffer512);
+ g_free(compressed512);
+ g_free(test512);
+
+}
+
+static void test_encode_decode_avx512(void)
+{
+ int i;
+ float time_raw = 0.0, time_512 = 0.0;
+ struct ResTime res;
+ for (i = 0; i < 10000; i++) {
+ encode_decode_range_avx512(&res);
+ time_raw += res.t_raw;
+ time_512 += res.t_512;
+ }
+ printf("Encode decode test:\n");
+ printf("Raw xbzrle_encode time is %f ms\n", time_raw);
+ printf("512 xbzrle_encode time is %f ms\n", time_512);
+}
+
+static void encode_decode_random(struct ResTime *res)
+{
+ uint8_t *buffer = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *compressed = g_malloc(XBZRLE_PAGE_SIZE);
+ uint8_t *test = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *buffer512 = g_malloc0(XBZRLE_PAGE_SIZE);
+ uint8_t *compressed512 = g_malloc(XBZRLE_PAGE_SIZE);
+ uint8_t *test512 = g_malloc0(XBZRLE_PAGE_SIZE);
+ int i = 0, rc = 0, rc512 = 0;
+ int dlen = 0, dlen512 = 0;
+
+ int diff_len = g_test_rand_int_range(0, XBZRLE_PAGE_SIZE - 1);
+ /* store the index of diff */
+ int dirty_index[diff_len];
+ for (int j = 0; j < diff_len; j++) {
+ dirty_index[j] = g_test_rand_int_range(0, XBZRLE_PAGE_SIZE - 1);
+ }
+ for (i = diff_len - 1; i >= 0; i--) {
+ buffer[dirty_index[i]] = i;
+ test[dirty_index[i]] = i + 4;
+ buffer512[dirty_index[i]] = i;
+ test512[dirty_index[i]] = i + 4;
+ }
+
+ time_t t_start, t_end, t_start512, t_end512;
+ t_start = clock();
+ dlen = xbzrle_encode_buffer(test, buffer, XBZRLE_PAGE_SIZE, compressed,
+ XBZRLE_PAGE_SIZE);
+ t_end = clock();
+ float time_val = difftime(t_end, t_start);
+ rc = xbzrle_decode_buffer(compressed, dlen, test, XBZRLE_PAGE_SIZE);
+ g_assert(rc < XBZRLE_PAGE_SIZE);
+
+ t_start512 = clock();
+ dlen512 = xbzrle_encode_buffer_avx512(test512, buffer512, XBZRLE_PAGE_SIZE,
+ compressed512, XBZRLE_PAGE_SIZE);
+ t_end512 = clock();
+ float time_val512 = difftime(t_end512, t_start512);
+ rc512 = xbzrle_decode_buffer(compressed512, dlen512, test512, XBZRLE_PAGE_SIZE);
+ g_assert(rc512 < XBZRLE_PAGE_SIZE);
+
+ res->t_raw = time_val;
+ res->t_512 = time_val512;
+
+ g_free(buffer);
+ g_free(compressed);
+ g_free(test);
+ g_free(buffer512);
+ g_free(compressed512);
+ g_free(test512);
+
+}
+
+static void test_encode_decode_random_avx512(void)
+{
+ int i;
+ float time_raw = 0.0, time_512 = 0.0;
+ struct ResTime res;
+ for (i = 0; i < 10000; i++) {
+ encode_decode_random(&res);
+ time_raw += res.t_raw;
+ time_512 += res.t_512;
+ }
+ printf("Random test:\n");
+ printf("Raw xbzrle_encode time is %f ms\n", time_raw);
+ printf("512 xbzrle_encode time is %f ms\n", time_512);
+}
+#endif
+
+int main(int argc, char **argv)
+{
+ g_test_init(&argc, &argv, NULL);
+ g_test_rand_int();
+ #if defined(CONFIG_AVX512BW_OPT)
+ if (likely(is_cpu_support_avx512bw)) {
+ g_test_add_func("/xbzrle/encode_decode_zero", test_encode_decode_zero_avx512);
+ g_test_add_func("/xbzrle/encode_decode_unchanged",
+ test_encode_decode_unchanged_avx512);
+ g_test_add_func("/xbzrle/encode_decode_1_byte", test_encode_decode_1_byte_avx512);
+ g_test_add_func("/xbzrle/encode_decode_overflow",
+ test_encode_decode_overflow_avx512);
+ g_test_add_func("/xbzrle/encode_decode", test_encode_decode_avx512);
+ g_test_add_func("/xbzrle/encode_decode_random", test_encode_decode_random_avx512);
+ }
+ #endif
+ return g_test_run();
+}
@@ -16,6 +16,35 @@
#define XBZRLE_PAGE_SIZE 4096
+int (*xbzrle_encode_buffer_func)(uint8_t *, uint8_t *, int,
+ uint8_t *, int) = xbzrle_encode_buffer;
+#if defined(CONFIG_AVX512BW_OPT)
+#include "qemu/cpuid.h"
+static void __attribute__((constructor)) init_cpu_flag(void)
+{
+ unsigned max = __get_cpuid_max(0, NULL);
+ int a, b, c, d;
+ if (max >= 1) {
+ __cpuid(1, a, b, c, d);
+ /* We must check that AVX is not just available, but usable. */
+ if ((c & bit_OSXSAVE) && (c & bit_AVX) && max >= 7) {
+ int bv;
+ __asm("xgetbv" : "=a"(bv), "=d"(d) : "c"(0));
+ __cpuid_count(7, 0, a, b, c, d);
+ /* 0xe6:
+ * XCR0[7:5] = 111b (OPMASK state, upper 256-bit of ZMM0-ZMM15
+ * and ZMM16-ZMM31 state are enabled by OS)
+ * XCR0[2:1] = 11b (XMM state and YMM state are enabled by OS)
+ */
+ if ((bv & 0xe6) == 0xe6 && (b & bit_AVX512BW)) {
+ xbzrle_encode_buffer_func = xbzrle_encode_buffer_avx512;
+ }
+ }
+ }
+ return ;
+}
+#endif
+
static void test_uleb(void)
{
uint32_t i, val;
@@ -54,7 +83,7 @@ static void test_encode_decode_zero(void)
buffer[1000 + diff_len + 5] = 105;
/* encode zero page */
- dlen = xbzrle_encode_buffer(buffer, buffer, XBZRLE_PAGE_SIZE, compressed,
+ dlen = xbzrle_encode_buffer_func(buffer, buffer, XBZRLE_PAGE_SIZE, compressed,
XBZRLE_PAGE_SIZE);
g_assert(dlen == 0);
@@ -78,7 +107,7 @@ static void test_encode_decode_unchanged(void)
test[1000 + diff_len + 5] = 109;
/* test unchanged buffer */
- dlen = xbzrle_encode_buffer(test, test, XBZRLE_PAGE_SIZE, compressed,
+ dlen = xbzrle_encode_buffer_func(test, test, XBZRLE_PAGE_SIZE, compressed,
XBZRLE_PAGE_SIZE);
g_assert(dlen == 0);
@@ -96,7 +125,7 @@ static void test_encode_decode_1_byte(void)
test[XBZRLE_PAGE_SIZE - 1] = 1;
- dlen = xbzrle_encode_buffer(buffer, test, XBZRLE_PAGE_SIZE, compressed,
+ dlen = xbzrle_encode_buffer_func(buffer, test, XBZRLE_PAGE_SIZE, compressed,
XBZRLE_PAGE_SIZE);
g_assert(dlen == (uleb128_encode_small(&buf[0], 4095) + 2));
@@ -121,7 +150,7 @@ static void test_encode_decode_overflow(void)
}
/* encode overflow */
- rc = xbzrle_encode_buffer(buffer, test, XBZRLE_PAGE_SIZE, compressed,
+ rc = xbzrle_encode_buffer_func(buffer, test, XBZRLE_PAGE_SIZE, compressed,
XBZRLE_PAGE_SIZE);
g_assert(rc == -1);
@@ -152,7 +181,7 @@ static void encode_decode_range(void)
test[1000 + diff_len + 5] = 109;
/* test encode/decode */
- dlen = xbzrle_encode_buffer(test, buffer, XBZRLE_PAGE_SIZE, compressed,
+ dlen = xbzrle_encode_buffer_func(test, buffer, XBZRLE_PAGE_SIZE, compressed,
XBZRLE_PAGE_SIZE);
rc = xbzrle_decode_buffer(compressed, dlen, test, XBZRLE_PAGE_SIZE);
Unit test code is in test-xbzrle.c, and benchmark code is in xbzrle-bench.c for performance benchmarking. we have modified xbzrle-bench.c to address CI problem. Signed-off-by: ling xu <ling1.xu@intel.com> Co-authored-by: Zhou Zhao <zhou.zhao@intel.com> Co-authored-by: Jun Jin <jun.i.jin@intel.com> --- tests/bench/meson.build | 4 + tests/bench/xbzrle-bench.c | 469 +++++++++++++++++++++++++++++++++++++ tests/unit/test-xbzrle.c | 39 ++- 3 files changed, 507 insertions(+), 5 deletions(-) create mode 100644 tests/bench/xbzrle-bench.c