Re: [PATCH v2] net/vhost: add pmd xstats

["Yang, Zhiyong" <zhiyong.yang@intel.com>]

Hi, yuanhan:
Thanks so much for your detailed comments. 

> -----Original Message-----
> From: Yuanhan Liu [mailto:yuanhan.liu@linux.intel.com]
> Sent: Wednesday, September 14, 2016 2:20 PM
> To: Yang, Zhiyong <zhiyong.yang@intel.com>
> Cc: dev@dpdk.org; thomas.monjalon@6wind.com; pmatilai@redhat.com
> Subject: Re: [PATCH v2] net/vhost: add pmd xstats
> 
> On Fri, Sep 09, 2016 at 04:15:27PM +0800, Zhiyong Yang wrote:
> > +struct vhost_xstats {
> > +	uint64_t stat[16];
> > +};
> > +
> >  struct vhost_queue {
> >  	int vid;
> >  	rte_atomic32_t allow_queuing;
> > @@ -85,7 +89,8 @@ struct vhost_queue {
> >  	uint64_t missed_pkts;
> >  	uint64_t rx_bytes;
> >  	uint64_t tx_bytes;
> 
> I'd suggest to put those statistic counters to vhost_stats struct, which could
> simplify the xstats_reset code a bit.
> 

I consider this point when I define it, but those statistic counters are used by pmd stats, 
not only by pmd xstats,  I'm not clear if  I can modify those code.  If permitted, 
I will do it as you said.

> And please do it in two patches, one to introduce vhost_stats, another one
> to add xstats.
> 

Ok.

> > -};
> > +	struct vhost_xstats xstats;
> > +	};
> 
> A format issue here.
> 

Naming issue? such as struct vhost_xstats vhost_stats;?

> >
> >  struct pmd_internal {
> >  	char *dev_name;
> > @@ -127,6 +132,274 @@ struct rte_vhost_vring_state {
> >
> >  static struct rte_vhost_vring_state *vring_states[RTE_MAX_ETHPORTS];
> >
> > +enum rte_vhostqueue_rxtx {
> 
> Don't use "rte_" prefix for internal function, vars, etc. "rte_" prefix is
> reserved for those that will be exported for public use.
> 

Ok, I will modify it.

> > +	RTE_VHOSTQUEUE_RX = 0,
> > +	RTE_VHOSTQUEUE_TX = 1
> > +};
> > +
> > +#define RTE_ETH_VHOST_XSTATS_NAME_SIZE 64
> 
> ditto.
> 

Ok, I will modify it.

> > +
> > +struct rte_vhost_xstats_name_off {
> 
> ditto.
> 

Ok, I will modify it.

> > +	char name[RTE_ETH_VHOST_XSTATS_NAME_SIZE];
> > +	uint64_t offset;
> > +};
> > +
> > +/* [rt]_qX_ is prepended to the name string here */ static void
> > +vhost_dev_xstats_reset(struct rte_eth_dev *dev) {
> > +	struct vhost_queue *vqrx = NULL;
> > +	struct vhost_queue *vqtx = NULL;
> > +	unsigned int i = 0;
> > +
> > +	for (i = 0; i < dev->data->nb_rx_queues; i++) {
> > +		if (!dev->data->rx_queues[i])
> > +			continue;
> > +		vqrx = (struct vhost_queue *)dev->data->rx_queues[i];
> 
> Unnecessary cast.
> 
The definition of rx_queues is  void **rx_queues; when we use it to access its
Data member,   Maybe explicit cast is needed, otherwise, we have to cast
Every time when using it.

> > +		vqrx->rx_pkts = 0;
> > +		vqrx->rx_bytes = 0;
> > +		vqrx->missed_pkts = 0;
> > +		memset(&vqrx->xstats, 0, sizeof(vqrx->xstats));
> > +	}
> > +	for (i = 0; i < dev->data->nb_tx_queues; i++) {
> > +		if (!dev->data->tx_queues[i])
> > +			continue;
> > +		vqtx = (struct vhost_queue *)dev->data->tx_queues[i];
> > +		vqtx->tx_pkts = 0;
> > +		vqtx->tx_bytes = 0;
> > +		vqtx->missed_pkts = 0;
> > +		memset(&vqtx->xstats, 0, sizeof(vqtx->xstats));
> > +	}
> > +}
> > +
> > +static int
> > +vhost_dev_xstats_get_names(struct rte_eth_dev *dev,
> > +			   struct rte_eth_xstat_name *xstats_names,
> > +			   __rte_unused unsigned int limit)
> 
> The typical way is to put __rte_unused after the key word.
> 

Ok.

> > +{
> > +	unsigned int i = 0;
> > +	unsigned int t = 0;
> > +	int count = 0;
> > +	int nstats = dev->data->nb_rx_queues * VHOST_NB_RXQ_XSTATS
> > +			+ dev->data->nb_tx_queues *
> VHOST_NB_TXQ_XSTATS;
> > +
> > +	if (xstats_names) {
> 
> I know you are following virtio pmd style, but you don't have to. I'd suggest
> to return early for (!xstats_names) case, then we could save one indention
> level for following code block.
> 

OK.

> > +		for (i = 0; i < dev->data->nb_rx_queues; i++) {
> > +			struct vhost_queue *rxvq = dev->data-
> >rx_queues[i];
> > +
> > +			if (!rxvq)
> > +				continue;
> > +			for (t = 0; t < VHOST_NB_RXQ_XSTATS; t++) {
> > +				snprintf(xstats_names[count].name,
> > +					 sizeof(xstats_names[count].name),
> > +					 "rx_q%u_%s", i,
> > +					 rte_vhost_rxq_stat_strings[t].name);
> > +				count++;
> > +			}
> > +		}
> > +		for (i = 0; i < dev->data->nb_tx_queues; i++) {
> > +			struct vhost_queue *txvq = dev->data-
> >tx_queues[i];
> > +
> > +			if (!txvq)
> > +				continue;
> > +			for (t = 0; t < VHOST_NB_TXQ_XSTATS; t++) {
> > +				snprintf(xstats_names[count].name,
> > +					 sizeof(xstats_names[count].name),
> > +					 "tx_q%u_%s", i,
> > +					 rte_vhost_txq_stat_strings[t].name);
> > +				count++;
> > +			}
> > +		}
> > +		return count;
> > +	}
> > +	return nstats;
> > +}
> > +
> > +static int
> > +vhost_dev_xstats_get(struct rte_eth_dev *dev, struct rte_eth_xstat
> *xstats,
> > +		     unsigned int n)
> > +{
> > +	unsigned int i;
> > +	unsigned int t;
> > +	unsigned int count = 0;
> > +
> > +	unsigned int nxstats = dev->data->nb_rx_queues *
> VHOST_NB_RXQ_XSTATS
> > +				+ dev->data->nb_tx_queues *
> VHOST_NB_TXQ_XSTATS;
> > +
> > +	if (n < nxstats)
> > +		return nxstats;
> > +
> > +	for (i = 0; i < dev->data->nb_rx_queues; i++) {
> > +		struct vhost_queue *rxvq =
> > +			(struct vhost_queue *)dev->data->rx_queues[i];
> 
> Unnecessary cast.
> 

Ok. I will remove it.

> > +
> > +		if (!rxvq)
> > +			continue;
> > +
> > +		for (t = 0; t < VHOST_NB_RXQ_XSTATS; t++) {
> > +			xstats[count].value = *(uint64_t *)(((char *)rxvq)
> > +				+ rte_vhost_rxq_stat_strings[t].offset);
> > +			count++;
> > +		}
> > +	}
> > +
> > +	for (i = 0; i < dev->data->nb_tx_queues; i++) {
> > +		struct vhost_queue *txvq =
> > +			(struct vhost_queue *)dev->data->tx_queues[i];
> > +
> > +		if (!txvq)
> > +			continue;
> > +
> > +		for (t = 0; t < VHOST_NB_TXQ_XSTATS; t++) {
> > +			xstats[count].value = *(uint64_t *)(((char *)txvq)
> > +				+ rte_vhost_txq_stat_strings[t].offset);
> > +			count++;
> > +		}
> > +	}
> > +
> > +	return count;
> > +}
> > +
> > +static void
> > +vhost_update_packet_xstats(struct vhost_queue *vq,
> > +			   struct rte_mbuf **bufs,
> > +			   uint16_t nb_rxtx,
> > +			   uint16_t nb_bufs,
> > +			   enum rte_vhostqueue_rxtx vqueue_rxtx) {
> > +	uint32_t pkt_len = 0;
> > +	uint64_t i = 0;
> > +	uint64_t index;
> > +	struct ether_addr *ea = NULL;
> > +	struct vhost_xstats *xstats_update = &vq->xstats;
> > +
> > +	for (i = 0; i < nb_rxtx ; i++) {
> > +		pkt_len = bufs[i]->pkt_len;
> > +		if (pkt_len == 64) {
> > +			xstats_update->stat[1]++;
> > +
> Unnecessary blank line.
> 
Ok. I will remove it.

> > +		} else if (pkt_len > 64 && pkt_len < 1024) {
> > +			index = (sizeof(pkt_len) * 8)
> > +				- __builtin_clz(pkt_len) - 5;
> > +			xstats_update->stat[index]++;
> > +		} else {
> > +			if (pkt_len < 64)
> > +				xstats_update->stat[0]++;
> > +			else if (pkt_len <= 1522)
> > +				xstats_update->stat[6]++;
> > +			else if (pkt_len > 1522)
> > +				xstats_update->stat[7]++;
> > +		}
> > +
> > +		ea = rte_pktmbuf_mtod(bufs[i], struct ether_addr *);
> > +		if (is_multicast_ether_addr(ea)) {
> > +			if (is_broadcast_ether_addr(ea))
> > +				/* broadcast++; */
> > +				xstats_update->stat[8]++;
> > +			else
> > +				/* multicast++; */
> > +				xstats_update->stat[9]++;
> 
> The comment could be avoided if you define a field in vhost_stats struct like
> "broadcast" or "multicast". I don't object the way Harry proposed tough, to
> use enum to access the stat array.
> 

I agree with you and Harry and will do like that.

> > +		}
> > +	}
> > +	/* non-multi/broadcast, multi/broadcast, including those
> > +	 * that were discarded or not sent.
> 
> Hmmm, I don't follow it. You may want to reword it.
> 
> > from rfc2863
> 
> Which section and which page?
> 
The packets received are not considered "discarded", because receiving packets via
Memory, not by physical NIC. Mainly for the number of transmit the packets
RFC2863 page 35  ifOutUcastPkts(non-multi/broadcast)
 Page 42 ifHCOutMulticastPkts
 Page 42 ifHCOutBroadcastPkts

> 	--yliu