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tests/atomic_add-bench: add -m option to use mutexes

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This allows us to use atomic-add-bench as a microbenchmark
for evaluating qemu_mutex_lock's performance.

Signed-off-by: Emilio G. Cota <cota@braap.org>
[cherry picked from https://github.com/cota/qemu/commit/f04f34df]
Signed-off-by: Peter Xu <peterx@redhat.com>
Message-Id: <20180425025459.5258-2-peterx@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Emilio G. Cota 2018-04-25 10:54:56 +08:00 committed by Paolo Bonzini
parent 6c090d4a75
commit 70c31264af
1 changed files with 17 additions and 2 deletions
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19
tests/atomic_add-bench.c
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@ -8,6 +8,7 @@ struct thread_info {
} QEMU_ALIGNED(64);
struct count {
QemuMutex lock;
unsigned long val;
} QEMU_ALIGNED(64);
@ -18,11 +19,13 @@ static unsigned int n_ready_threads;
static struct count *counts;
static unsigned int duration = 1;
static unsigned int range = 1024;
static bool use_mutex;
static bool test_start;
static bool test_stop;
static const char commands_string[] =
" -n = number of threads\n"
" -m = use mutexes instead of atomic increments\n"
" -d = duration in seconds\n"
" -r = range (will be rounded up to pow2)";
@ -59,7 +62,13 @@ static void *thread_func(void *arg)
info->r = xorshift64star(info->r);
index = info->r & (range - 1);
atomic_inc(&counts[index].val);
if (use_mutex) {
qemu_mutex_lock(&counts[index].lock);
counts[index].val += 1;
qemu_mutex_unlock(&counts[index].lock);
} else {
atomic_inc(&counts[index].val);
}
}
return NULL;
}
@ -91,6 +100,9 @@ static void create_threads(void)
th_info = g_new(struct thread_info, n_threads);
counts = qemu_memalign(64, sizeof(*counts) * range);
memset(counts, 0, sizeof(*counts) * range);
for (i = 0; i < range; i++) {
qemu_mutex_init(&counts[i].lock);
}
for (i = 0; i < n_threads; i++) {
struct thread_info *info = &th_info[i];
@ -131,7 +143,7 @@ static void parse_args(int argc, char *argv[])
int c;
for (;;) {
c = getopt(argc, argv, "hd:n:r:");
c = getopt(argc, argv, "hd:n:mr:");
if (c < 0) {
break;
}
@ -145,6 +157,9 @@ static void parse_args(int argc, char *argv[])
case 'n':
n_threads = atoi(optarg);
break;
case 'm':
use_mutex = true;
break;
case 'r':
range = pow2ceil(atoi(optarg));
break;