[dpdk-dev] [PATCH 2/2] vhost: use fixed Virtio-net header len packed ring

[Maxime Coquelin]

Welcome back Chenbo,

On 10/9/20 8:36 AM, Xia, Chenbo wrote:
> Hi Maxime,
> 
>> -----Original Message-----
>> From: Maxime Coquelin <maxime.coquelin at redhat.com>
>> Sent: Thursday, October 1, 2020 6:12 PM
>> To: dev at dpdk.org; Xia, Chenbo <chenbo.xia at intel.com>; Liu, Yong
>> <yong.liu at intel.com>
>> Cc: Maxime Coquelin <maxime.coquelin at redhat.com>
>> Subject: [PATCH 2/2] vhost: use fixed Virtio-net header len packed ring
>>
>> This small optimization uses static the Virtio-net header len
> 
> Better use 'the static Virtio-net header length' here when you apply the
> patch 😊. With this fix:

I did the change when applying, thanks!
Maxime

> Reviewed-by: Chenbo Xia <chenbo.xia at intel.com>
> 
>> in packed datapath, since Virtio-net header cannot be the
>> legacy one in case of packed ring.
>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
>> ---
>>  lib/librte_vhost/virtio_net.c | 11 ++++++-----
>>  1 file changed, 6 insertions(+), 5 deletions(-)
>>
>> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
>> index 0a0bea1a5a..5865fa5f65 100644
>> --- a/lib/librte_vhost/virtio_net.c
>> +++ b/lib/librte_vhost/virtio_net.c
>> @@ -1147,7 +1147,7 @@ vhost_enqueue_single_packed(struct virtio_net *dev,
>>  	uint16_t buf_id = 0;
>>  	uint32_t len = 0;
>>  	uint16_t desc_count;
>> -	uint32_t size = pkt->pkt_len + dev->vhost_hlen;
>> +	uint32_t size = pkt->pkt_len + sizeof(struct
>> virtio_net_hdr_mrg_rxbuf);
>>  	uint16_t num_buffers = 0;
>>  	uint32_t buffer_len[vq->size];
>>  	uint16_t buffer_buf_id[vq->size];
>> @@ -1262,7 +1262,7 @@ virtio_dev_rx_batch_packed(struct virtio_net *dev,
>>  	uint16_t avail_idx = vq->last_avail_idx;
>>  	uint64_t desc_addrs[PACKED_BATCH_SIZE];
>>  	struct virtio_net_hdr_mrg_rxbuf *hdrs[PACKED_BATCH_SIZE];
>> -	uint32_t buf_offset = dev->vhost_hlen;
>> +	uint32_t buf_offset = sizeof(struct virtio_net_hdr_mrg_rxbuf);
>>  	uint64_t lens[PACKED_BATCH_SIZE];
>>  	uint16_t ids[PACKED_BATCH_SIZE];
>>  	uint16_t i;
>> @@ -1308,7 +1308,8 @@ virtio_dev_rx_batch_packed(struct virtio_net *dev,
>>  		rte_prefetch0((void *)(uintptr_t)desc_addrs[i]);
>>  		hdrs[i] = (struct virtio_net_hdr_mrg_rxbuf *)
>>  					(uintptr_t)desc_addrs[i];
>> -		lens[i] = pkts[i]->pkt_len + dev->vhost_hlen;
>> +		lens[i] = pkts[i]->pkt_len +
>> +			sizeof(struct virtio_net_hdr_mrg_rxbuf);
>>  	}
>>
>>  	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
>> @@ -2277,7 +2278,7 @@ vhost_reserve_avail_batch_packed(struct virtio_net
>> *dev,
>>  	struct virtio_net_hdr *hdr;
>>  	uint64_t lens[PACKED_BATCH_SIZE];
>>  	uint64_t buf_lens[PACKED_BATCH_SIZE];
>> -	uint32_t buf_offset = dev->vhost_hlen;
>> +	uint32_t buf_offset = sizeof(struct virtio_net_hdr_mrg_rxbuf);
>>  	uint16_t flags, i;
>>
>>  	if (unlikely(avail_idx & PACKED_BATCH_MASK))
>> @@ -2354,7 +2355,7 @@ virtio_dev_tx_batch_packed(struct virtio_net *dev,
>>  			   struct rte_mbuf **pkts)
>>  {
>>  	uint16_t avail_idx = vq->last_avail_idx;
>> -	uint32_t buf_offset = dev->vhost_hlen;
>> +	uint32_t buf_offset = sizeof(struct virtio_net_hdr_mrg_rxbuf);
>>  	uintptr_t desc_addrs[PACKED_BATCH_SIZE];
>>  	uint16_t ids[PACKED_BATCH_SIZE];
>>  	uint16_t i;
>> --
>> 2.26.2
>