Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754647Ab3ESUDP (ORCPT ); Sun, 19 May 2013 16:03:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:63341 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754283Ab3ESUDN (ORCPT ); Sun, 19 May 2013 16:03:13 -0400 Date: Sun, 19 May 2013 23:03:21 +0300 From: "Michael S. Tsirkin" To: "Narasimhan, Sriram" Cc: "rusty@rustcorp.com.au" , "virtualization@lists.linux-foundation.org" , "kvm@vger.kernel.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Jason Wang Subject: Re: [PATCH] virtio-net: Reporting traffic queue distribution statistics through ethtool Message-ID: <20130519200320.GA27407@redhat.com> References: <1368735869-31076-1-git-send-email-sriram.narasimhan@hp.com> <20130519112800.GG19883@redhat.com> <228BD1969E90E94D8805535E22CE8EFF063CF133@G9W0717.americas.hpqcorp.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <228BD1969E90E94D8805535E22CE8EFF063CF133@G9W0717.americas.hpqcorp.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 12359 Lines: 372 On Sun, May 19, 2013 at 04:09:48PM +0000, Narasimhan, Sriram wrote: > Hi Michael, > > I was getting all packets on the same inbound queue which > is why I added this support to virtio-net (and some more > instrumentation at tun as well). But, it turned out to be > my misconfiguration - I did not enable IFF_MULTI_QUEUE on > the tap device, so the real_num_tx_queues on tap netdev was > always 1 (no tx distribution at tap). Interesting that qemu didn't fail. > I am thinking about > adding a -q option to tunctl to specify multi-queue flag on > the tap device. Absolutely. > Yes, number of exits will be most useful. I will look into > adding the other statistics you mention. > > Sriram Pls note you'll need to switch to virtqueue_kick_prepare to detect exits: virtqueue_kick doesn't let you know whether there was an exit. Also, it's best to make this a separate patch from the one adding per-queue stats. > -----Original Message----- > From: Michael S. Tsirkin [mailto:mst@redhat.com] > Sent: Sunday, May 19, 2013 4:28 AM > To: Narasimhan, Sriram > Cc: rusty@rustcorp.com.au; virtualization@lists.linux-foundation.org; kvm@vger.kernel.org; netdev@vger.kernel.org; linux-kernel@vger.kernel.org > Subject: Re: [PATCH] virtio-net: Reporting traffic queue distribution statistics through ethtool > > On Thu, May 16, 2013 at 01:24:29PM -0700, Sriram Narasimhan wrote: > > This patch allows virtio-net driver to report traffic distribution > > to inbound/outbound queues through ethtool -S. The per_cpu > > virtnet_stats is split into receive and transmit stats and are > > maintained on a per receive_queue and send_queue basis. > > virtnet_stats() is modified to aggregate interface level statistics > > from per-queue statistics. Sample output below: > > > > Thanks for the patch. The idea itself looks OK to me. > Ben Hutchings already sent some comments > so I won't repeat them. Some minor more comments > and questions below. > > > NIC statistics: > > rxq0: rx_packets: 4357802 > > rxq0: rx_bytes: 292642052 > > txq0: tx_packets: 824540 > > txq0: tx_bytes: 55256404 > > rxq1: rx_packets: 0 > > rxq1: rx_bytes: 0 > > txq1: tx_packets: 1094268 > > txq1: tx_bytes: 73328316 > > rxq2: rx_packets: 0 > > rxq2: rx_bytes: 0 > > txq2: tx_packets: 1091466 > > txq2: tx_bytes: 73140566 > > rxq3: rx_packets: 0 > > rxq3: rx_bytes: 0 > > txq3: tx_packets: 1093043 > > txq3: tx_bytes: 73246142 > > Interesting. This example implies that all packets are coming in > through the same RX queue - is this right? > If yes that's worth exploring - could be a tun bug - > and shows how this patch is useful. > > > Signed-off-by: Sriram Narasimhan > > BTW, while you are looking at the stats, one other interesting > thing to add could be checking more types of stats: number of exits, > queue full errors, etc. > > > --- > > drivers/net/virtio_net.c | 157 +++++++++++++++++++++++++++++++++++++--------- > > 1 files changed, 128 insertions(+), 29 deletions(-) > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > index 3c23fdc..3c58c52 100644 > > --- a/drivers/net/virtio_net.c > > +++ b/drivers/net/virtio_net.c > > @@ -41,15 +41,46 @@ module_param(gso, bool, 0444); > > > > #define VIRTNET_DRIVER_VERSION "1.0.0" > > > > -struct virtnet_stats { > > - struct u64_stats_sync tx_syncp; > > +struct virtnet_rx_stats { > > struct u64_stats_sync rx_syncp; > > - u64 tx_bytes; > > + u64 rx_packets; > > + u64 rx_bytes; > > +}; > > + > > +struct virtnet_tx_stats { > > + struct u64_stats_sync tx_syncp; > > u64 tx_packets; > > + u64 tx_bytes; > > +}; > > > > - u64 rx_bytes; > > - u64 rx_packets; > > I think maintaining the stats in a per-queue data structure like this is > fine. if # of CPUs == # of queues which is typical, we use same amount > of memory. And each queue access is under a lock, > or from napi thread, so no races either. > > > +struct virtnet_ethtool_stats { > > + char desc[ETH_GSTRING_LEN]; > > + int type; > > + int size; > > + int offset; > > +}; > > + > > +enum {VIRTNET_STATS_TX, VIRTNET_STATS_RX}; > > + > > +#define VIRTNET_RX_STATS_INFO(_struct, _field) \ > > + {#_field, VIRTNET_STATS_RX, FIELD_SIZEOF(_struct, _field), \ > > + offsetof(_struct, _field)} > > + > > +#define VIRTNET_TX_STATS_INFO(_struct, _field) \ > > + {#_field, VIRTNET_STATS_TX, FIELD_SIZEOF(_struct, _field), \ > > + offsetof(_struct, _field)} > > + > > +static const struct virtnet_ethtool_stats virtnet_et_rx_stats[] = { > > + VIRTNET_RX_STATS_INFO(struct virtnet_rx_stats, rx_packets), > > + VIRTNET_RX_STATS_INFO(struct virtnet_rx_stats, rx_bytes) > > +}; > > +#define VIRTNET_RX_STATS_NUM (ARRAY_SIZE(virtnet_et_rx_stats)) > > + > > +static const struct virtnet_ethtool_stats virtnet_et_tx_stats[] = { > > + VIRTNET_TX_STATS_INFO(struct virtnet_tx_stats, tx_packets), > > + VIRTNET_TX_STATS_INFO(struct virtnet_tx_stats, tx_bytes) > > }; > > +#define VIRTNET_TX_STATS_NUM (ARRAY_SIZE(virtnet_et_tx_stats)) > > I'd prefer a full name: virtnet_ethtool_tx_stats, or > just virtnet_tx_stats. > > > > > /* Internal representation of a send virtqueue */ > > struct send_queue { > > @@ -61,6 +92,9 @@ struct send_queue { > > > > /* Name of the send queue: output.$index */ > > char name[40]; > > + > > + /* Active send queue statistics */ > > + struct virtnet_tx_stats stats; > > }; > > > > /* Internal representation of a receive virtqueue */ > > @@ -81,6 +115,9 @@ struct receive_queue { > > > > /* Name of this receive queue: input.$index */ > > char name[40]; > > + > > + /* Active receive queue statistics */ > > + struct virtnet_rx_stats stats; > > }; > > > > struct virtnet_info { > > @@ -109,9 +146,6 @@ struct virtnet_info { > > /* enable config space updates */ > > bool config_enable; > > > > - /* Active statistics */ > > - struct virtnet_stats __percpu *stats; > > - > > /* Work struct for refilling if we run low on memory. */ > > struct delayed_work refill; > > > > @@ -330,7 +364,7 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len) > > { > > struct virtnet_info *vi = rq->vq->vdev->priv; > > struct net_device *dev = vi->dev; > > - struct virtnet_stats *stats = this_cpu_ptr(vi->stats); > > + struct virtnet_rx_stats *stats = &rq->stats; > > struct sk_buff *skb; > > struct page *page; > > struct skb_vnet_hdr *hdr; > > @@ -650,8 +684,7 @@ static void free_old_xmit_skbs(struct send_queue *sq) > > { > > struct sk_buff *skb; > > unsigned int len; > > - struct virtnet_info *vi = sq->vq->vdev->priv; > > - struct virtnet_stats *stats = this_cpu_ptr(vi->stats); > > + struct virtnet_tx_stats *stats = &sq->stats; > > > > while ((skb = virtqueue_get_buf(sq->vq, &len)) != NULL) { > > pr_debug("Sent skb %p\n", skb); > > @@ -841,24 +874,25 @@ static struct rtnl_link_stats64 *virtnet_stats(struct net_device *dev, > > struct rtnl_link_stats64 *tot) > > { > > struct virtnet_info *vi = netdev_priv(dev); > > - int cpu; > > + int i; > > unsigned int start; > > > > - for_each_possible_cpu(cpu) { > > - struct virtnet_stats *stats = per_cpu_ptr(vi->stats, cpu); > > + for (i = 0; i < vi->max_queue_pairs; i++) { > > + struct virtnet_tx_stats *tstats = &vi->sq[i].stats; > > + struct virtnet_rx_stats *rstats = &vi->rq[i].stats; > > u64 tpackets, tbytes, rpackets, rbytes; > > > > do { > > - start = u64_stats_fetch_begin_bh(&stats->tx_syncp); > > - tpackets = stats->tx_packets; > > - tbytes = stats->tx_bytes; > > - } while (u64_stats_fetch_retry_bh(&stats->tx_syncp, start)); > > + start = u64_stats_fetch_begin_bh(&tstats->tx_syncp); > > + tpackets = tstats->tx_packets; > > + tbytes = tstats->tx_bytes; > > + } while (u64_stats_fetch_retry_bh(&tstats->tx_syncp, start)); > > > > do { > > - start = u64_stats_fetch_begin_bh(&stats->rx_syncp); > > - rpackets = stats->rx_packets; > > - rbytes = stats->rx_bytes; > > - } while (u64_stats_fetch_retry_bh(&stats->rx_syncp, start)); > > + start = u64_stats_fetch_begin_bh(&rstats->rx_syncp); > > + rpackets = rstats->rx_packets; > > + rbytes = rstats->rx_bytes; > > + } while (u64_stats_fetch_retry_bh(&rstats->rx_syncp, start)); > > > > tot->rx_packets += rpackets; > > tot->tx_packets += tpackets; > > @@ -1177,12 +1211,83 @@ static void virtnet_get_channels(struct net_device *dev, > > channels->other_count = 0; > > } > > > > +static void virtnet_get_stat_strings(struct net_device *dev, > > + u32 stringset, > > + u8 *data) > > +{ > > + struct virtnet_info *vi = netdev_priv(dev); > > + int i, j; > > + > > + switch (stringset) { > > + case ETH_SS_STATS: > > + for (i = 0; i < vi->max_queue_pairs; i++) { > > + for (j = 0; j < VIRTNET_RX_STATS_NUM; j++) { > > + sprintf(data, "rxq%d: %s", i, > > + virtnet_et_rx_stats[j].desc); > > + data += ETH_GSTRING_LEN; > > + } > > + for (j = 0; j < VIRTNET_TX_STATS_NUM; j++) { > > + sprintf(data, "txq%d: %s", i, > > + virtnet_et_tx_stats[j].desc); > > + data += ETH_GSTRING_LEN; > > + } > > + } > > + break; > > + } > > +} > > + > > +static int virtnet_get_sset_count(struct net_device *dev, int stringset) > > +{ > > + struct virtnet_info *vi = netdev_priv(dev); > > + switch (stringset) { > > + case ETH_SS_STATS: > > + return vi->max_queue_pairs * > > + (VIRTNET_RX_STATS_NUM + VIRTNET_TX_STATS_NUM); > > + default: > > + return -EINVAL; > > + } > > +} > > + > > +static void virtnet_get_ethtool_stats(struct net_device *dev, > > + struct ethtool_stats *stats, > > + u64 *data) > > +{ > > + struct virtnet_info *vi = netdev_priv(dev); > > + unsigned int i, base; > > + unsigned int start; > > + > > + for (i = 0, base = 0; i < vi->max_queue_pairs; i++) { > > + struct virtnet_tx_stats *tstats = &vi->sq[i].stats; > > + struct virtnet_rx_stats *rstats = &vi->rq[i].stats; > > + > > + do { > > + start = u64_stats_fetch_begin_bh(&rstats->rx_syncp); > > + data[base] = rstats->rx_packets; > > + data[base+1] = rstats->rx_bytes; > > nitpicking: > We normally has spaces around +, like this: > data[base + 1] = rstats->rx_bytes; > > > + } while (u64_stats_fetch_retry_bh(&rstats->rx_syncp, start)); > > + > > + base += VIRTNET_RX_STATS_NUM; > > + > > + do { > > + start = u64_stats_fetch_begin_bh(&tstats->tx_syncp); > > + data[base] = tstats->tx_packets; > > + data[base+1] = tstats->tx_bytes; > > > nitpicking: > Here, something strange happened to indentation. > > > + } while (u64_stats_fetch_retry_bh(&tstats->tx_syncp, start)); > > + > > + base += VIRTNET_TX_STATS_NUM; > > + } > > +} > > + > > + > > static const struct ethtool_ops virtnet_ethtool_ops = { > > .get_drvinfo = virtnet_get_drvinfo, > > .get_link = ethtool_op_get_link, > > .get_ringparam = virtnet_get_ringparam, > > .set_channels = virtnet_set_channels, > > .get_channels = virtnet_get_channels, > > + .get_strings = virtnet_get_stat_strings, > > + .get_sset_count = virtnet_get_sset_count, > > + .get_ethtool_stats = virtnet_get_ethtool_stats, > > }; > > > > #define MIN_MTU 68 > > @@ -1531,14 +1636,11 @@ static int virtnet_probe(struct virtio_device *vdev) > > vi->dev = dev; > > vi->vdev = vdev; > > vdev->priv = vi; > > - vi->stats = alloc_percpu(struct virtnet_stats); > > err = -ENOMEM; > > - if (vi->stats == NULL) > > - goto free; > > > > vi->vq_index = alloc_percpu(int); > > if (vi->vq_index == NULL) > > - goto free_stats; > > + goto free; > > > > mutex_init(&vi->config_lock); > > vi->config_enable = true; > > @@ -1616,8 +1718,6 @@ free_vqs: > > virtnet_del_vqs(vi); > > free_index: > > free_percpu(vi->vq_index); > > -free_stats: > > - free_percpu(vi->stats); > > free: > > free_netdev(dev); > > return err; > > @@ -1653,7 +1753,6 @@ static void virtnet_remove(struct virtio_device *vdev) > > flush_work(&vi->config_work); > > > > free_percpu(vi->vq_index); > > - free_percpu(vi->stats); > > free_netdev(vi->dev); > > } > > Thanks! > > > -- > > 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/