On Thu, Jul 07, 2022 at 10:44:08AM +0800, Guo Zhi wrote:
> Prior implementation only use one descriptor for each io event, which
> does't test code of descriptor chain. More importantly, one descriptor
> will not use indirect feature even indirect feature is specified. Use
> random length scatterlists here to test descriptor chain.
>
> Signed-off-by: Guo Zhi <qtxuning1999@xxxxxxxxxxx>
> ---
> tools/virtio/virtio_test.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/tools/virtio/virtio_test.c b/tools/virtio/virtio_test.c
> index 1ecd64271..363695b33 100644
> --- a/tools/virtio/virtio_test.c
> +++ b/tools/virtio/virtio_test.c
> @@ -20,6 +20,7 @@
> #include "../../drivers/vhost/test.h"
>
> #define RANDOM_BATCH -1
> +#define MAX_SG_FRAGS 8UL
> #define ALIGN 4096
> #define RINGSIZE 256
> #define TEST_BUF_NUM 0x100000
> @@ -172,7 +173,8 @@ static void wait_for_interrupt(struct vdev_info *dev)
> static void run_test(struct vdev_info *dev, struct vq_info *vq,
> bool delayed, int batch, int reset_n, int bufs)
> {
> - struct scatterlist sl;
> + struct scatterlist sg[MAX_SG_FRAGS];
> + int sg_size = 0;
> long started = 0, completed = 0, next_reset = reset_n;
> long completed_before, started_before;
> int r, test = 1;
> @@ -197,8 +199,11 @@ static void run_test(struct vdev_info *dev, struct vq_info *vq,
>
> while (started < bufs &&
> (started - completed) < batch) {
> - sg_init_one(&sl, dev->buf, dev->buf_size);
> - r = virtqueue_add_outbuf(vq->vq, &sl, 1,
> + sg_size = random() % (MAX_SG_FRAGS - 1) + 1;
> + sg_init_table(sg, sg_size);
> + for (int i = 0; i < sg_size; ++i)
> + sg_set_buf(&sg[i], dev->buf + i, 0x1);
> + r = virtqueue_add_outbuf(vq->vq, sg, sg_size,
> dev->buf + started,
> GFP_ATOMIC);
> if (unlikely(r != 0)) {
random on data path is pretty expensive.
I would suggest get an array size from user (and maybe a seed?) and
pregenerate some numbers, then reuse.
> --
> 2.17.1
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