[dpdk-dev] [PATCH] vhost: vhost injects interrupts to guest for each packet
Tan, Jianfeng
jianfeng.tan at intel.com
Mon Sep 21 11:40:35 CEST 2015
> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Huawei Xie
> Sent: Monday, September 21, 2015 4:16 PM
> To: dev at dpdk.org
> Subject: [dpdk-dev] [PATCH] vhost: vhost injects interrupts to guest for each
> packet
>
> In merge-able RX path, vhost injects interrupts to guest for each packet.
> This should degrade performance a lot.
> This patch fixes this issue by injecting one interrupt for a batch of packets.
>
> Signed-off-by: Huawei Xie <huawei.xie at intel.com>
> ---
> lib/librte_vhost/vhost_rxtx.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c
> index 0d07338..9d3165a 100644
> --- a/lib/librte_vhost/vhost_rxtx.c
> +++ b/lib/librte_vhost/vhost_rxtx.c
> @@ -496,7 +496,7 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t
> queue_id,
> "to get enough desc from "
> "vring\n",
> dev->device_fh);
> - return pkt_idx;
> + goto merge_rx_exit;
> } else {
> update_secure_len(vq, res_cur_idx,
> &secure_len, &vec_idx);
> res_cur_idx++;
> @@ -523,7 +523,10 @@ virtio_dev_merge_rx(struct virtio_net *dev,
> uint16_t queue_id,
>
> *(volatile uint16_t *)&vq->used->idx += entry_success;
> vq->last_used_idx = res_cur_idx;
> + }
>
> +merge_rx_exit:
> + if (likely(pkt_idx)) {
> /* flush used->idx update before we read avail->flags. */
> rte_mb();
>
> @@ -532,7 +535,7 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t
> queue_id,
> eventfd_write((int)vq->callfd, 1);
> }
>
> - return count;
> + return pkt_idx;
> }
>
> uint16_t
> --
Acked-by: Jianfeng Tan <Jianfeng.tan at intel.com>
> 1.9.3
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