tools/virtio: Add --batch=random option

So we can test with non-deterministic batches in flight.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Link: https://lore.kernel.org/r/20200418102217.32327-4-eperezma@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/tools/virtio/virtio_test.c b/tools/virtio/virtio_test.c
index c30de90..4a2b9d1 100644 (file)
--- a/tools/virtio/virtio_test.c
+++ b/tools/virtio/virtio_test.c
@@ -19,6 +19,8 @@
 #include <linux/virtio_ring.h>
 #include "../../drivers/vhost/test.h"
 
+#define RANDOM_BATCH -1
+
 /* Unused */
 void *__kmalloc_fake, *__kfree_ignore_start, *__kfree_ignore_end;
 
@@ -161,6 +163,7 @@ static void run_test(struct vdev_info *dev, struct vq_info *vq,
        int r, test = 1;
        unsigned len;
        long long spurious = 0;
+       const bool random_batch = batch == RANDOM_BATCH;
        r = ioctl(dev->control, VHOST_TEST_RUN, &test);
        assert(r >= 0);
        for (;;) {
@@ -168,6 +171,9 @@ static void run_test(struct vdev_info *dev, struct vq_info *vq,
                completed_before = completed;
                started_before = started;
                do {
+                       if (random_batch)
+                               batch = (random() % vq->vring.num) + 1;
+
                        while (started < bufs &&
                               (started - completed) < batch) {
                                sg_init_one(&sl, dev->buf, dev->buf_size);
@@ -275,7 +281,7 @@ static void help(void)
                " [--no-event-idx]"
                " [--no-virtio-1]"
                " [--delayed-interrupt]"
-               " [--batch=N]"
+               " [--batch=random/N]"
                "\n");
 }
 
@@ -312,9 +318,13 @@ int main(int argc, char **argv)
                        delayed = true;
                        break;
                case 'b':
-                       batch = strtol(optarg, NULL, 10);
-                       assert(batch > 0);
-                       assert(batch < (long)INT_MAX + 1);
+                       if (0 == strcmp(optarg, "random")) {
+                               batch = RANDOM_BATCH;
+                       } else {
+                               batch = strtol(optarg, NULL, 10);
+                               assert(batch > 0);
+                               assert(batch < (long)INT_MAX + 1);
+                       }
                        break;
                default:
                        assert(0);