From: Jason Wang <jasowang@redhat.com>
To: Tiwei Bie <tiwei.bie@intel.com>, "Michael S. Tsirkin" <mst@redhat.com>
Cc: virtualization@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
virtio-dev@lists.oasis-open.org, wexu@redhat.com,
jfreimann@redhat.com, maxime.coquelin@redhat.com
Subject: Re: [PATCH net-next v3 00/13] virtio: support packed ring
Date: Wed, 21 Nov 2018 21:46:06 +0800 [thread overview]
Message-ID: <84e80a22-75cc-5b9d-7f6e-980e41850e00@redhat.com> (raw)
In-Reply-To: <20181121124233.GA32189@debian>
On 2018/11/21 下午8:42, Tiwei Bie wrote:
> On Wed, Nov 21, 2018 at 07:20:27AM -0500, Michael S. Tsirkin wrote:
>> On Wed, Nov 21, 2018 at 06:03:17PM +0800, Tiwei Bie wrote:
>>> Hi,
>>>
>>> This patch set implements packed ring support in virtio driver.
>>>
>>> A performance test between pktgen (pktgen_sample03_burst_single_flow.sh)
>>> and DPDK vhost (testpmd/rxonly/vhost-PMD) has been done, I saw
>>> ~30% performance gain in packed ring in this case.
>> Thanks a lot, this is very exciting!
>> Dave, given the holiday, attempts to wrap up the 1.1 spec and the
>> patchset size I would very much appreciate a bit more time for
>> review. Say until Nov 28?
>>
>>> To make this patch set work with below patch set for vhost,
>>> some hacks are needed to set the _F_NEXT flag in indirect
>>> descriptors (this should be fixed in vhost):
>>>
>>> https://lkml.org/lkml/2018/7/3/33
>> Could you pls clarify - do you mean it doesn't yet work with vhost
>> because of a vhost bug, and to test it with the linked patches
>> you had to hack in _F_NEXT? Because I do not see _F_NEXT
>> in indirect descriptors in this patch (which is fine).
>> Or did I miss it?
> You didn't miss anything. :)
>
> I think it's a small bug in vhost, which Jason may fix very
> quickly, so I didn't post it. Below is the hack I used:
Good catch. I didn't notice the subtle difference since split ring
requires for it.
Let me fix it in next version.
Thanks.
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index cd7e755484e3..42faea7d8cf8 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -980,6 +980,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
> unsigned int i, n, err_idx;
> u16 head, id;
> dma_addr_t addr;
> + int c = 0;
>
> head = vq->packed.next_avail_idx;
> desc = alloc_indirect_packed(total_sg, gfp);
> @@ -1001,8 +1002,9 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
> if (vring_mapping_error(vq, addr))
> goto unmap_release;
>
> - desc[i].flags = cpu_to_le16(n < out_sgs ?
> - 0 : VRING_DESC_F_WRITE);
> + desc[i].flags = cpu_to_le16((n < out_sgs ?
> + 0 : VRING_DESC_F_WRITE) |
> + (++c == total_sg ? 0 : VRING_DESC_F_NEXT));
> desc[i].addr = cpu_to_le64(addr);
> desc[i].len = cpu_to_le32(sg->length);
> i++;
next prev parent reply other threads:[~2018-11-21 13:46 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-21 10:03 [PATCH net-next v3 00/13] virtio: support packed ring Tiwei Bie
2018-11-21 10:03 ` [PATCH net-next v3 01/13] virtio: add packed ring types and macros Tiwei Bie
2018-11-30 8:10 ` Jason Wang
2018-11-30 9:53 ` Tiwei Bie
2018-11-30 12:47 ` Michael S. Tsirkin
2018-11-30 13:01 ` Maxime Coquelin
2018-11-30 13:52 ` Michael S. Tsirkin
2018-11-30 15:37 ` Tiwei Bie
2018-11-30 15:53 ` Michael S. Tsirkin
2018-11-30 16:24 ` Tiwei Bie
2018-11-30 16:46 ` Michael S. Tsirkin
2018-12-01 2:03 ` Tiwei Bie
2018-11-21 10:03 ` [PATCH net-next v3 02/13] virtio_ring: add _split suffix for split ring functions Tiwei Bie
2018-11-21 10:03 ` [PATCH net-next v3 03/13] virtio_ring: put split ring functions together Tiwei Bie
2018-11-21 10:03 ` [PATCH net-next v3 04/13] virtio_ring: put split ring fields in a sub struct Tiwei Bie
2018-11-21 10:03 ` [PATCH net-next v3 05/13] virtio_ring: introduce debug helpers Tiwei Bie
2018-11-21 10:03 ` [PATCH net-next v3 06/13] virtio_ring: introduce helper for indirect feature Tiwei Bie
2018-11-21 10:03 ` [PATCH net-next v3 07/13] virtio_ring: allocate desc state for split ring separately Tiwei Bie
2018-11-21 10:03 ` [PATCH net-next v3 08/13] virtio_ring: extract split ring handling from ring creation Tiwei Bie
2018-11-21 10:03 ` [PATCH net-next v3 09/13] virtio_ring: cache whether we will use DMA API Tiwei Bie
2018-11-21 10:03 ` [PATCH net-next v3 10/13] virtio_ring: introduce packed ring support Tiwei Bie
2018-11-21 10:03 ` [PATCH net-next v3 11/13] virtio_ring: leverage event idx in packed ring Tiwei Bie
2018-11-21 10:03 ` [PATCH net-next v3 12/13] virtio_ring: disable packed ring on unsupported transports Tiwei Bie
2018-11-21 10:03 ` [PATCH net-next v3 13/13] virtio_ring: advertize packed ring layout Tiwei Bie
2018-11-21 12:20 ` [PATCH net-next v3 00/13] virtio: support packed ring Michael S. Tsirkin
2018-11-21 12:42 ` Tiwei Bie
2018-11-21 13:46 ` Jason Wang [this message]
2018-11-21 17:37 ` David Miller
2018-11-27 6:08 ` Michael S. Tsirkin
2018-11-27 6:18 ` David Miller
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