From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: Tiwei Bie <tiwei.bie@intel.com>, zhihong.wang@intel.com, dev@dpdk.org
Cc: stable@dpdk.org
Subject: Re: [dpdk-stable] [PATCH 3/5] net/virtio: fix in-order Tx path for packed ring
Date: Thu, 21 Feb 2019 12:16:24 +0100 [thread overview]
Message-ID: <0cc7c8b6-ec40-ee9e-7873-e655908d68cc@redhat.com> (raw)
In-Reply-To: <20190219105951.31046-4-tiwei.bie@intel.com>
On 2/19/19 11:59 AM, Tiwei Bie wrote:
> When IN_ORDER feature is negotiated, device may just write out a
> single used descriptor for a batch of buffers:
>
> """
> Some devices always use descriptors in the same order in which they
> have been made available. These devices can offer the VIRTIO_F_IN_ORDER
> feature. If negotiated, this knowledge allows devices to notify the
> use of a batch of buffers to the driver by only writing out a single
> used descriptor with the Buffer ID corresponding to the last descriptor
> in the batch.
>
> The device then skips forward in the ring according to the size of the
> batch. The driver needs to look up the used Buffer ID and calculate the
> batch size to be able to advance to where the next used descriptor will
> be written by the device.
> """
>
> But the Tx path of packed ring can't handle this. With this patch,
> when IN_ORDER is negotiated, driver will manage the IDs linearly,
> look up the used buffer ID and advance to the next used descriptor
> that will be written by the device.
>
> Fixes: 892dc798fa9c ("net/virtio: implement Tx path for packed queues")
> Cc: stable@dpdk.org
>
> Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
> ---
> drivers/net/virtio/virtio_ethdev.c | 4 +-
> drivers/net/virtio/virtio_rxtx.c | 69 ++++++++++++++++++++++++------
> 2 files changed, 59 insertions(+), 14 deletions(-)
>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Thanks,
Maxime
prev parent reply other threads:[~2019-02-21 11:16 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190219105951.31046-1-tiwei.bie@intel.com>
2019-02-19 10:59 ` [dpdk-stable] [PATCH 1/5] net/virtio: fix Tx desc cleanup " Tiwei Bie
2019-02-21 11:05 ` Maxime Coquelin
2019-02-19 10:59 ` [dpdk-stable] [PATCH 2/5] net/virtio: fix in-order Tx path for split ring Tiwei Bie
2019-02-21 11:08 ` Maxime Coquelin
2019-02-19 10:59 ` [dpdk-stable] [PATCH 3/5] net/virtio: fix in-order Tx path for packed ring Tiwei Bie
2019-02-21 11:16 ` Maxime Coquelin [this message]
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