Re: [dpdk-dev] [PATCH] virtio: split virtio rx/tx queue

["Xie, Huawei" <huawei.xie@intel.com>]

On 5/30/2016 11:00 AM, Yuanhan Liu wrote:
> On Mon, May 30, 2016 at 02:40:00AM +0000, Xie, Huawei wrote:
>> On 5/27/2016 5:06 PM, Yuanhan Liu wrote:
>>> On Tue, May 24, 2016 at 09:38:32PM +0800, Huawei Xie wrote:
>>>>  	vq->vq_ring_mem = mz->phys_addr;
>>>>  	vq->vq_ring_virt_mem = mz->addr;
>>>> -	PMD_INIT_LOG(DEBUG, "vq->vq_ring_mem:      0x%"PRIx64, (uint64_t)mz->phys_addr);
>>>> -	PMD_INIT_LOG(DEBUG, "vq->vq_ring_virt_mem: 0x%"PRIx64, (uint64_t)(uintptr_t)mz->addr);
>>>> -	vq->virtio_net_hdr_mz  = NULL;
>>>> -	vq->virtio_net_hdr_mem = 0;
>>>> +	PMD_INIT_LOG(DEBUG, "vq->vq_ring_mem:      0x%"PRIx64,
>>>> +		     (uint64_t)mz->phys_addr);
>>>> +	PMD_INIT_LOG(DEBUG, "vq->vq_ring_virt_mem: 0x%"PRIx64,
>>>> +		     (uint64_t)(uintptr_t)mz->addr);
>>>> +
>>>> +	hdr_mz = rte_memzone_reserve_aligned(vq_hdr_name, sz_hdr_mz, socket_id,
>>>> +					     0, RTE_CACHE_LINE_SIZE);
>>> We don't need allocate hdr_mz for Rx queue, and in such case, sz_hdr_mz
>>> is 0. I'm wondering what hdr_mz would be then, NULL?
>>>
>>> Anyway, you should skip the hdr_mz allocation for Rx queue, and I also
>>> would suggest you to move the vq_hdr_name setup here.
>> will check sz_hdr_mz before the zone allocation.
>>
>>
>>>> +	if (hdr_mz == NULL) {
>>>> +		if (rte_errno == EEXIST)
>>>> +			hdr_mz = rte_memzone_lookup(vq_hdr_name);
>>>> +		if (hdr_mz == NULL) {
>>>> +			ret = -ENOMEM;
>>>> +			goto fail_q_alloc;
>>>> +		}
>>>> +	}
>>>>  
>>> ...
>>>>  
>>>>  	PMD_INIT_FUNC_TRACE();
>>>>  	ret = virtio_dev_queue_setup(dev, VTNET_CQ, VTNET_SQ_CQ_QUEUE_IDX,
>>>> -			vtpci_queue_idx, 0, socket_id, &vq);
>>>> +			vtpci_queue_idx, 0, socket_id, (void **)&cvq);
>>> Unnecessary cast. Note that there are few others like that in this
>>> patch.
>> This cast is needed.
> Oh, right, indeed. Sorry.
>
>>>> -		PMD_RX_LOG(DEBUG, "dequeue:%d", num);
>>>> -		PMD_RX_LOG(DEBUG, "packet len:%d", len[0]);
>>>> +		PMD_RX_LOG(DEBUG, "dequeue:%d\n", num);
>>>> +		PMD_RX_LOG(DEBUG, "packet len:%d\n", len[0]);
>>> We should not append "\n" for PMD_RX_LOG; this macro alreadys does it.
>> Weird. Will remove it. Thanks.
>>
>>> Another note is that you might want to run checkpatch; I saw quite many
>>> warnings.
>> Had checked. The warnings are all due to 80 char limitation of
>> virtio_rxq_stats_strings. Just 4 or 5 chars cross 80 line limit. I
>> prefer to keep the fields aligned.
> Agreed. However, I was talking about others warnings.

ok, i see you are using checkpatch of newer Linux kernel.


>
> 	--yliu
>
> ---
> CHECK:BRACES: braces {} should be used on all arms of this statement
> #198: FILE: drivers/net/virtio/virtio_ethdev.c:343:

would fix this.

> +       if (queue_type == VTNET_RQ)
> [...]
> +       else if (queue_type == VTNET_TQ) {
> [...]
> +       } else if (queue_type == VTNET_CQ) {
> [...]
>
> CHECK:CAMELCASE: Avoid CamelCase: <PRIx64>
> #280: FILE: drivers/net/virtio/virtio_ethdev.c:404:
> +       PMD_INIT_LOG(DEBUG, "vq->vq_ring_mem:      0x%"PRIx64,
>
> CHECK:CONCATENATED_STRING: Concatenated strings should use spaces
> between elements
> #280: FILE: drivers/net/virtio/virtio_ethdev.c:404:
> +       PMD_INIT_LOG(DEBUG, "vq->vq_ring_mem:      0x%"PRIx64,
>
> CHECK:CONCATENATED_STRING: Concatenated strings should use spaces
> between elements
> #282: FILE: drivers/net/virtio/virtio_ethdev.c:406:
> +       PMD_INIT_LOG(DEBUG, "vq->vq_ring_virt_mem: 0x%"PRIx64,
>
> WARNING:UNSPECIFIED_INT: Prefer 'unsigned int' to bare use of 'unsigned'
> #482: FILE: drivers/net/virtio/virtio_ethdev.c:753:
> +       unsigned nstats = dev->data->nb_tx_queues * VIRTIO_NB_TXQ_XSTATS
> +
>
> WARNING:LONG_LINE: line over 80 characters
> #551: FILE: drivers/net/virtio/virtio_ethdev.c:819:
> +               memset(txvq->stats.size_bins, 0,
> sizeof(txvq->stats.size_bins[0]) * 8);
>
> WARNING:LONG_LINE: line over 80 characters
> #571: FILE: drivers/net/virtio/virtio_ethdev.c:832:
> +               memset(rxvq->stats.size_bins, 0,
> sizeof(rxvq->stats.size_bins[0]) * 8);

would fix this.

>
> CHECK:MULTIPLE_ASSIGNMENTS: multiple assignments should be avoided
> #1529: FILE: drivers/net/virtio/virtio_rxtx_simple.c:362:
> +       nb_commit = nb_pkts = RTE_MIN((vq->vq_free_cnt >> 1), nb_pkts);
>
> CHECK:SPACING: No space is necessary after a cast
> #1530: FILE: drivers/net/virtio/virtio_rxtx_simple.c:363:
> +       desc_idx = (uint16_t) (vq->vq_avail_idx & desc_idx_max);

All other warnings are due to the newer checkpatch script, and not
introduced by this patch, so wouldn't fix in this patch.
But i think some are better programming practice, like 'Concatenated
strings should use spaces between elements', so would post a patch to
fix them in virtio driver (if possible, all other drivers).