From: "Michael S. Tsirkin" <mst@redhat.com>
To: Guo Zhi <qtxuning1999@sjtu.edu.cn>
Cc: eperezma@redhat.com, linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v2 3/4] virtio_test: use random length scatterlists to test descriptor chain
Date: Thu, 7 Jul 2022 01:16:38 -0400 [thread overview]
Message-ID: <20220707011015-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20220707024409.1869-4-qtxuning1999@sjtu.edu.cn>
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.
> --
> 2.17.1
_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
prev parent reply other threads:[~2022-07-07 5:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20220707024409.1869-1-qtxuning1999@sjtu.edu.cn>
[not found] ` <20220707024409.1869-5-qtxuning1999@sjtu.edu.cn>
2022-07-07 4:59 ` [PATCH v2 4/4] virtio_test: enable indirection feature Michael S. Tsirkin
[not found] ` <2ff418ad-0ab8-1474-4308-2d163c1e6652@sjtu.edu.cn>
2022-07-07 5:59 ` Michael S. Tsirkin
[not found] ` <20220707024409.1869-3-qtxuning1999@sjtu.edu.cn>
2022-07-07 5:09 ` [PATCH v2 2/4] virtio_test: move magic number in code as defined constant Michael S. Tsirkin
[not found] ` <8c15f97f-df6d-9ec5-b9d3-c42350cde887@sjtu.edu.cn>
2022-07-07 7:36 ` Michael S. Tsirkin
[not found] ` <20220707024409.1869-4-qtxuning1999@sjtu.edu.cn>
2022-07-07 5:16 ` Michael S. Tsirkin [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220707011015-mutt-send-email-mst@kernel.org \
--to=mst@redhat.com \
--cc=eperezma@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=qtxuning1999@sjtu.edu.cn \
--cc=virtualization@lists.linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).