Messages in this thread | | | Date | Thu, 7 Jul 2022 14:24:02 +0800 | Subject | Re: [PATCH v2 3/4] virtio_test: use random length scatterlists to test descriptor chain | From | Guo Zhi <> |
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On 2022/7/7 13:16, Michael S. Tsirkin wrote: > 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@sjtu.edu.cn> >> --- >> 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. SGTM, I will prepare a random number array before add outbuf begin. > >> -- >> 2.17.1
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