| Message ID | c00b526f32d9f9a5cd2e98a212ee5306d6b6d71c.1700478183.git.hengqi@linux.alibaba.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | virtio-net: support dynamic coalescing moderation | expand |
On Mon, Nov 20, 2023 at 8:38 PM Heng Qi <hengqi@linux.alibaba.com> wrote: > > By comparing the traffic information in the complete napi processes, > let the virtio-net driver automatically adjust the coalescing > moderation parameters of each receive queue. > > Signed-off-by: Heng Qi <hengqi@linux.alibaba.com> > --- > v2->v3: > - Some minor modifications. > > v1->v2: > - Improved the judgment of dim switch conditions. > - Cancel the work when vq reset. > > drivers/net/virtio_net.c | 191 ++++++++++++++++++++++++++++++++++----- > 1 file changed, 169 insertions(+), 22 deletions(-) > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > index 69fe09e99b3c..bc32d5aae005 100644 > --- a/drivers/net/virtio_net.c > +++ b/drivers/net/virtio_net.c > @@ -19,6 +19,7 @@ > #include <linux/average.h> > #include <linux/filter.h> > #include <linux/kernel.h> > +#include <linux/dim.h> > #include <net/route.h> > #include <net/xdp.h> > #include <net/net_failover.h> > @@ -172,6 +173,17 @@ struct receive_queue { > > struct virtnet_rq_stats stats; > > + /* The number of rx notifications */ > + u16 calls; > + > + /* Is dynamic interrupt moderation enabled? */ > + bool dim_enabled; > + > + /* Dynamic Interrupt Moderation */ > + struct dim dim; > + > + u32 packets_in_napi; > + > struct virtnet_interrupt_coalesce intr_coal; > > /* Chain pages by the private ptr. */ > @@ -305,6 +317,9 @@ struct virtnet_info { > u8 duplex; > u32 speed; > > + /* Is rx dynamic interrupt moderation enabled? */ > + bool rx_dim_enabled; > + > /* Interrupt coalescing settings */ > struct virtnet_interrupt_coalesce intr_coal_tx; > struct virtnet_interrupt_coalesce intr_coal_rx; > @@ -2001,6 +2016,7 @@ static void skb_recv_done(struct virtqueue *rvq) > struct virtnet_info *vi = rvq->vdev->priv; > struct receive_queue *rq = &vi->rq[vq2rxq(rvq)]; > > + rq->calls++; > virtqueue_napi_schedule(&rq->napi, rvq); > } > > @@ -2141,6 +2157,26 @@ static void virtnet_poll_cleantx(struct receive_queue *rq) > } > } > > +static void virtnet_rx_dim_work(struct work_struct *work); > + > +static void virtnet_rx_dim_update(struct virtnet_info *vi, struct receive_queue *rq) > +{ > + struct dim_sample cur_sample = {}; > + > + if (!rq->packets_in_napi) > + return; > + > + u64_stats_update_begin(&rq->stats.syncp); > + dim_update_sample(rq->calls, > + u64_stats_read(&rq->stats.packets), > + u64_stats_read(&rq->stats.bytes), > + &cur_sample); > + u64_stats_update_end(&rq->stats.syncp); > + > + net_dim(&rq->dim, cur_sample); > + rq->packets_in_napi = 0; > +} > + > static int virtnet_poll(struct napi_struct *napi, int budget) > { > struct receive_queue *rq = > @@ -2149,17 +2185,22 @@ static int virtnet_poll(struct napi_struct *napi, int budget) > struct send_queue *sq; > unsigned int received; > unsigned int xdp_xmit = 0; > + bool napi_complete; > > virtnet_poll_cleantx(rq); > > received = virtnet_receive(rq, budget, &xdp_xmit); > + rq->packets_in_napi += received; > > if (xdp_xmit & VIRTIO_XDP_REDIR) > xdp_do_flush(); > > /* Out of packets? */ > - if (received < budget) > - virtqueue_napi_complete(napi, rq->vq, received); > + if (received < budget) { > + napi_complete = virtqueue_napi_complete(napi, rq->vq, received); > + if (napi_complete && rq->dim_enabled) > + virtnet_rx_dim_update(vi, rq); > + } > > if (xdp_xmit & VIRTIO_XDP_TX) { > sq = virtnet_xdp_get_sq(vi); > @@ -2179,6 +2220,7 @@ static void virtnet_disable_queue_pair(struct virtnet_info *vi, int qp_index) > virtnet_napi_tx_disable(&vi->sq[qp_index].napi); > napi_disable(&vi->rq[qp_index].napi); > xdp_rxq_info_unreg(&vi->rq[qp_index].xdp_rxq); > + cancel_work_sync(&vi->rq[qp_index].dim.work); > } > > static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index) > @@ -2196,6 +2238,9 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index) > if (err < 0) > goto err_xdp_reg_mem_model; > > + INIT_WORK(&vi->rq[qp_index].dim.work, virtnet_rx_dim_work); > + vi->rq[qp_index].dim.mode = DIM_CQ_PERIOD_MODE_START_FROM_EQE; So in V2, you explained it can be done here but I want to know why it must be done here. For example, the refill_work is initialized in alloc_queues(). > + > virtnet_napi_enable(vi->rq[qp_index].vq, &vi->rq[qp_index].napi); > virtnet_napi_tx_enable(vi, vi->sq[qp_index].vq, &vi->sq[qp_index].napi); > > @@ -2393,8 +2438,10 @@ static int virtnet_rx_resize(struct virtnet_info *vi, > > qindex = rq - vi->rq; > > - if (running) > + if (running) { > napi_disable(&rq->napi); > + cancel_work_sync(&rq->dim.work); > + } > > err = virtqueue_resize(rq->vq, ring_num, virtnet_rq_free_unused_buf); > if (err) > @@ -2403,8 +2450,10 @@ static int virtnet_rx_resize(struct virtnet_info *vi, > if (!try_fill_recv(vi, rq, GFP_KERNEL)) > schedule_delayed_work(&vi->refill, 0); > > - if (running) > + if (running) { > + INIT_WORK(&rq->dim.work, virtnet_rx_dim_work); > virtnet_napi_enable(rq->vq, &rq->napi); > + } > return err; > } > > @@ -3341,24 +3390,55 @@ static int virtnet_send_tx_notf_coal_cmds(struct virtnet_info *vi, > static int virtnet_send_rx_notf_coal_cmds(struct virtnet_info *vi, > struct ethtool_coalesce *ec) > { > + bool rx_ctrl_dim_on = !!ec->use_adaptive_rx_coalesce; > + bool update = false, switch_dim; > struct scatterlist sgs_rx; > int i; > > - vi->ctrl->coal_rx.rx_usecs = cpu_to_le32(ec->rx_coalesce_usecs); > - vi->ctrl->coal_rx.rx_max_packets = cpu_to_le32(ec->rx_max_coalesced_frames); > - sg_init_one(&sgs_rx, &vi->ctrl->coal_rx, sizeof(vi->ctrl->coal_rx)); > - > - if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL, > - VIRTIO_NET_CTRL_NOTF_COAL_RX_SET, > - &sgs_rx)) > - return -EINVAL; > + switch_dim = rx_ctrl_dim_on != vi->rx_dim_enabled; > + if (switch_dim) { > + if (rx_ctrl_dim_on) { > + if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL)) { So basically, I'm asking why we need to duplicate the check here? E.g caller has done the check for us: if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_NOTF_COAL)) ret = virtnet_send_notf_coal_cmds(vi, ec); else ret = virtnet_coal_params_supported(ec); ? Please also check other nested if/else, usually, too many levels of nesting is a hint that the logic needs to be optimized. Thanks
On Wed, Nov 22, 2023 at 1:52 PM Jason Wang <jasowang@redhat.com> wrote: > > On Mon, Nov 20, 2023 at 8:38 PM Heng Qi <hengqi@linux.alibaba.com> wrote: > > > > By comparing the traffic information in the complete napi processes, > > let the virtio-net driver automatically adjust the coalescing > > moderation parameters of each receive queue. > > > > Signed-off-by: Heng Qi <hengqi@linux.alibaba.com> > > --- > > v2->v3: > > - Some minor modifications. > > > > v1->v2: > > - Improved the judgment of dim switch conditions. > > - Cancel the work when vq reset. > > > > drivers/net/virtio_net.c | 191 ++++++++++++++++++++++++++++++++++----- > > 1 file changed, 169 insertions(+), 22 deletions(-) > > > > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c > > index 69fe09e99b3c..bc32d5aae005 100644 > > --- a/drivers/net/virtio_net.c > > +++ b/drivers/net/virtio_net.c > > @@ -19,6 +19,7 @@ > > #include <linux/average.h> > > #include <linux/filter.h> > > #include <linux/kernel.h> > > +#include <linux/dim.h> > > #include <net/route.h> > > #include <net/xdp.h> > > #include <net/net_failover.h> > > @@ -172,6 +173,17 @@ struct receive_queue { > > > > struct virtnet_rq_stats stats; > > > > + /* The number of rx notifications */ > > + u16 calls; > > + > > + /* Is dynamic interrupt moderation enabled? */ > > + bool dim_enabled; > > + > > + /* Dynamic Interrupt Moderation */ > > + struct dim dim; > > + > > + u32 packets_in_napi; > > + > > struct virtnet_interrupt_coalesce intr_coal; > > > > /* Chain pages by the private ptr. */ > > @@ -305,6 +317,9 @@ struct virtnet_info { > > u8 duplex; > > u32 speed; > > > > + /* Is rx dynamic interrupt moderation enabled? */ > > + bool rx_dim_enabled; > > + > > /* Interrupt coalescing settings */ > > struct virtnet_interrupt_coalesce intr_coal_tx; > > struct virtnet_interrupt_coalesce intr_coal_rx; > > @@ -2001,6 +2016,7 @@ static void skb_recv_done(struct virtqueue *rvq) > > struct virtnet_info *vi = rvq->vdev->priv; > > struct receive_queue *rq = &vi->rq[vq2rxq(rvq)]; > > > > + rq->calls++; > > virtqueue_napi_schedule(&rq->napi, rvq); > > } > > > > @@ -2141,6 +2157,26 @@ static void virtnet_poll_cleantx(struct receive_queue *rq) > > } > > } > > > > +static void virtnet_rx_dim_work(struct work_struct *work); > > + > > +static void virtnet_rx_dim_update(struct virtnet_info *vi, struct receive_queue *rq) > > +{ > > + struct dim_sample cur_sample = {}; > > + > > + if (!rq->packets_in_napi) > > + return; > > + > > + u64_stats_update_begin(&rq->stats.syncp); > > + dim_update_sample(rq->calls, > > + u64_stats_read(&rq->stats.packets), > > + u64_stats_read(&rq->stats.bytes), > > + &cur_sample); > > + u64_stats_update_end(&rq->stats.syncp); > > + > > + net_dim(&rq->dim, cur_sample); > > + rq->packets_in_napi = 0; > > +} > > + > > static int virtnet_poll(struct napi_struct *napi, int budget) > > { > > struct receive_queue *rq = > > @@ -2149,17 +2185,22 @@ static int virtnet_poll(struct napi_struct *napi, int budget) > > struct send_queue *sq; > > unsigned int received; > > unsigned int xdp_xmit = 0; > > + bool napi_complete; > > > > virtnet_poll_cleantx(rq); > > > > received = virtnet_receive(rq, budget, &xdp_xmit); > > + rq->packets_in_napi += received; > > > > if (xdp_xmit & VIRTIO_XDP_REDIR) > > xdp_do_flush(); > > > > /* Out of packets? */ > > - if (received < budget) > > - virtqueue_napi_complete(napi, rq->vq, received); > > + if (received < budget) { > > + napi_complete = virtqueue_napi_complete(napi, rq->vq, received); > > + if (napi_complete && rq->dim_enabled) > > + virtnet_rx_dim_update(vi, rq); > > + } > > > > if (xdp_xmit & VIRTIO_XDP_TX) { > > sq = virtnet_xdp_get_sq(vi); > > @@ -2179,6 +2220,7 @@ static void virtnet_disable_queue_pair(struct virtnet_info *vi, int qp_index) > > virtnet_napi_tx_disable(&vi->sq[qp_index].napi); > > napi_disable(&vi->rq[qp_index].napi); > > xdp_rxq_info_unreg(&vi->rq[qp_index].xdp_rxq); > > + cancel_work_sync(&vi->rq[qp_index].dim.work); > > } > > > > static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index) > > @@ -2196,6 +2238,9 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index) > > if (err < 0) > > goto err_xdp_reg_mem_model; > > > > + INIT_WORK(&vi->rq[qp_index].dim.work, virtnet_rx_dim_work); > > + vi->rq[qp_index].dim.mode = DIM_CQ_PERIOD_MODE_START_FROM_EQE; > > So in V2, you explained it can be done here but I want to know why it > must be done here. > > For example, the refill_work is initialized in alloc_queues(). > > > + > > virtnet_napi_enable(vi->rq[qp_index].vq, &vi->rq[qp_index].napi); > > virtnet_napi_tx_enable(vi, vi->sq[qp_index].vq, &vi->sq[qp_index].napi); > > > > @@ -2393,8 +2438,10 @@ static int virtnet_rx_resize(struct virtnet_info *vi, > > > > qindex = rq - vi->rq; > > > > - if (running) > > + if (running) { > > napi_disable(&rq->napi); > > + cancel_work_sync(&rq->dim.work); > > + } > > > > err = virtqueue_resize(rq->vq, ring_num, virtnet_rq_free_unused_buf); > > if (err) > > @@ -2403,8 +2450,10 @@ static int virtnet_rx_resize(struct virtnet_info *vi, > > if (!try_fill_recv(vi, rq, GFP_KERNEL)) > > schedule_delayed_work(&vi->refill, 0); > > > > - if (running) > > + if (running) { > > + INIT_WORK(&rq->dim.work, virtnet_rx_dim_work); > > virtnet_napi_enable(rq->vq, &rq->napi); > > + } > > return err; > > } > > > > @@ -3341,24 +3390,55 @@ static int virtnet_send_tx_notf_coal_cmds(struct virtnet_info *vi, > > static int virtnet_send_rx_notf_coal_cmds(struct virtnet_info *vi, > > struct ethtool_coalesce *ec) > > { > > + bool rx_ctrl_dim_on = !!ec->use_adaptive_rx_coalesce; > > + bool update = false, switch_dim; > > struct scatterlist sgs_rx; > > int i; > > > > - vi->ctrl->coal_rx.rx_usecs = cpu_to_le32(ec->rx_coalesce_usecs); > > - vi->ctrl->coal_rx.rx_max_packets = cpu_to_le32(ec->rx_max_coalesced_frames); > > - sg_init_one(&sgs_rx, &vi->ctrl->coal_rx, sizeof(vi->ctrl->coal_rx)); > > - > > - if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL, > > - VIRTIO_NET_CTRL_NOTF_COAL_RX_SET, > > - &sgs_rx)) > > - return -EINVAL; > > + switch_dim = rx_ctrl_dim_on != vi->rx_dim_enabled; > > + if (switch_dim) { > > + if (rx_ctrl_dim_on) { > > + if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL)) { > > So basically, I'm asking why we need to duplicate the check here? > > E.g caller has done the check for us: > > if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_NOTF_COAL)) > ret = virtnet_send_notf_coal_cmds(vi, ec); > else > ret = virtnet_coal_params_supported(ec); Speak too fast, they have different features :( But the point still, the logic needs some optimizations to reduce the levels of nesting if/else. Thanks > > ? > > Please also check other nested if/else, usually, too many levels of > nesting is a hint that the logic needs to be optimized. > > Thanks
On Mon, 20 Nov 2023 20:37:34 +0800, Heng Qi wrote: <...> > @@ -2179,6 +2220,7 @@ static void virtnet_disable_queue_pair(struct virtnet_info *vi, int qp_index) > virtnet_napi_tx_disable(&vi->sq[qp_index].napi); > napi_disable(&vi->rq[qp_index].napi); > xdp_rxq_info_unreg(&vi->rq[qp_index].xdp_rxq); > + cancel_work_sync(&vi->rq[qp_index].dim.work); I'm not sure, but please check if here may cause deadlock: rtnl_lock held -> .ndo_stop -> virtnet_disable_queue_pair() -> cancel_work_sync() -> virtnet_rx_dim_work() -> rtnl_lock() > } > > static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index) <...>
在 2023/11/22 下午1:52, Jason Wang 写道: > On Mon, Nov 20, 2023 at 8:38 PM Heng Qi <hengqi@linux.alibaba.com> wrote: >> By comparing the traffic information in the complete napi processes, >> let the virtio-net driver automatically adjust the coalescing >> moderation parameters of each receive queue. >> >> Signed-off-by: Heng Qi <hengqi@linux.alibaba.com> >> --- >> v2->v3: >> - Some minor modifications. >> >> v1->v2: >> - Improved the judgment of dim switch conditions. >> - Cancel the work when vq reset. >> >> drivers/net/virtio_net.c | 191 ++++++++++++++++++++++++++++++++++----- >> 1 file changed, 169 insertions(+), 22 deletions(-) >> >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >> index 69fe09e99b3c..bc32d5aae005 100644 >> --- a/drivers/net/virtio_net.c >> +++ b/drivers/net/virtio_net.c >> @@ -19,6 +19,7 @@ >> #include <linux/average.h> >> #include <linux/filter.h> >> #include <linux/kernel.h> >> +#include <linux/dim.h> >> #include <net/route.h> >> #include <net/xdp.h> >> #include <net/net_failover.h> >> @@ -172,6 +173,17 @@ struct receive_queue { >> >> struct virtnet_rq_stats stats; >> >> + /* The number of rx notifications */ >> + u16 calls; >> + >> + /* Is dynamic interrupt moderation enabled? */ >> + bool dim_enabled; >> + >> + /* Dynamic Interrupt Moderation */ >> + struct dim dim; >> + >> + u32 packets_in_napi; >> + >> struct virtnet_interrupt_coalesce intr_coal; >> >> /* Chain pages by the private ptr. */ >> @@ -305,6 +317,9 @@ struct virtnet_info { >> u8 duplex; >> u32 speed; >> >> + /* Is rx dynamic interrupt moderation enabled? */ >> + bool rx_dim_enabled; >> + >> /* Interrupt coalescing settings */ >> struct virtnet_interrupt_coalesce intr_coal_tx; >> struct virtnet_interrupt_coalesce intr_coal_rx; >> @@ -2001,6 +2016,7 @@ static void skb_recv_done(struct virtqueue *rvq) >> struct virtnet_info *vi = rvq->vdev->priv; >> struct receive_queue *rq = &vi->rq[vq2rxq(rvq)]; >> >> + rq->calls++; >> virtqueue_napi_schedule(&rq->napi, rvq); >> } >> >> @@ -2141,6 +2157,26 @@ static void virtnet_poll_cleantx(struct receive_queue *rq) >> } >> } >> >> +static void virtnet_rx_dim_work(struct work_struct *work); >> + >> +static void virtnet_rx_dim_update(struct virtnet_info *vi, struct receive_queue *rq) >> +{ >> + struct dim_sample cur_sample = {}; >> + >> + if (!rq->packets_in_napi) >> + return; >> + >> + u64_stats_update_begin(&rq->stats.syncp); >> + dim_update_sample(rq->calls, >> + u64_stats_read(&rq->stats.packets), >> + u64_stats_read(&rq->stats.bytes), >> + &cur_sample); >> + u64_stats_update_end(&rq->stats.syncp); >> + >> + net_dim(&rq->dim, cur_sample); >> + rq->packets_in_napi = 0; >> +} >> + >> static int virtnet_poll(struct napi_struct *napi, int budget) >> { >> struct receive_queue *rq = >> @@ -2149,17 +2185,22 @@ static int virtnet_poll(struct napi_struct *napi, int budget) >> struct send_queue *sq; >> unsigned int received; >> unsigned int xdp_xmit = 0; >> + bool napi_complete; >> >> virtnet_poll_cleantx(rq); >> >> received = virtnet_receive(rq, budget, &xdp_xmit); >> + rq->packets_in_napi += received; >> >> if (xdp_xmit & VIRTIO_XDP_REDIR) >> xdp_do_flush(); >> >> /* Out of packets? */ >> - if (received < budget) >> - virtqueue_napi_complete(napi, rq->vq, received); >> + if (received < budget) { >> + napi_complete = virtqueue_napi_complete(napi, rq->vq, received); >> + if (napi_complete && rq->dim_enabled) >> + virtnet_rx_dim_update(vi, rq); >> + } >> >> if (xdp_xmit & VIRTIO_XDP_TX) { >> sq = virtnet_xdp_get_sq(vi); >> @@ -2179,6 +2220,7 @@ static void virtnet_disable_queue_pair(struct virtnet_info *vi, int qp_index) >> virtnet_napi_tx_disable(&vi->sq[qp_index].napi); >> napi_disable(&vi->rq[qp_index].napi); >> xdp_rxq_info_unreg(&vi->rq[qp_index].xdp_rxq); >> + cancel_work_sync(&vi->rq[qp_index].dim.work); >> } >> >> static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index) >> @@ -2196,6 +2238,9 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index) >> if (err < 0) >> goto err_xdp_reg_mem_model; >> >> + INIT_WORK(&vi->rq[qp_index].dim.work, virtnet_rx_dim_work); >> + vi->rq[qp_index].dim.mode = DIM_CQ_PERIOD_MODE_START_FROM_EQE; > So in V2, you explained it can be done here but I want to know why it > must be done here. It is not must be done here. We can place it in probe and make sure that INIT_WORK() is done before napi is enabled for the first time. So then I'll don't call INIT_WORK() every time after "napi_disable -> napi_enable" happens, and use the following process: Call INIT_WORK() in the driver probe and do cancel_work() after each related napi_disable. This will be clearer. Additionally, Yinjun Zhang found that cancel_work_sync() will cause a deadlock when ndo_stop and virtnet_rx_dim_work occurs at the same time, so cancel_work() will be used. > > For example, the refill_work is initialized in alloc_queues(). > >> + >> virtnet_napi_enable(vi->rq[qp_index].vq, &vi->rq[qp_index].napi); >> virtnet_napi_tx_enable(vi, vi->sq[qp_index].vq, &vi->sq[qp_index].napi); >> >> @@ -2393,8 +2438,10 @@ static int virtnet_rx_resize(struct virtnet_info *vi, >> >> qindex = rq - vi->rq; >> >> - if (running) >> + if (running) { >> napi_disable(&rq->napi); >> + cancel_work_sync(&rq->dim.work); >> + } >> >> err = virtqueue_resize(rq->vq, ring_num, virtnet_rq_free_unused_buf); >> if (err) >> @@ -2403,8 +2450,10 @@ static int virtnet_rx_resize(struct virtnet_info *vi, >> if (!try_fill_recv(vi, rq, GFP_KERNEL)) >> schedule_delayed_work(&vi->refill, 0); >> >> - if (running) >> + if (running) { >> + INIT_WORK(&rq->dim.work, virtnet_rx_dim_work); >> virtnet_napi_enable(rq->vq, &rq->napi); >> + } >> return err; >> } >> >> @@ -3341,24 +3390,55 @@ static int virtnet_send_tx_notf_coal_cmds(struct virtnet_info *vi, >> static int virtnet_send_rx_notf_coal_cmds(struct virtnet_info *vi, >> struct ethtool_coalesce *ec) >> { >> + bool rx_ctrl_dim_on = !!ec->use_adaptive_rx_coalesce; >> + bool update = false, switch_dim; >> struct scatterlist sgs_rx; >> int i; >> >> - vi->ctrl->coal_rx.rx_usecs = cpu_to_le32(ec->rx_coalesce_usecs); >> - vi->ctrl->coal_rx.rx_max_packets = cpu_to_le32(ec->rx_max_coalesced_frames); >> - sg_init_one(&sgs_rx, &vi->ctrl->coal_rx, sizeof(vi->ctrl->coal_rx)); >> - >> - if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL, >> - VIRTIO_NET_CTRL_NOTF_COAL_RX_SET, >> - &sgs_rx)) >> - return -EINVAL; >> + switch_dim = rx_ctrl_dim_on != vi->rx_dim_enabled; >> + if (switch_dim) { >> + if (rx_ctrl_dim_on) { >> + if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL)) { > So basically, I'm asking why we need to duplicate the check here? Here is VIRTIO_NET_F_*VQ*_NOTF_COAL. > > E.g caller has done the check for us: > > if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_NOTF_COAL)) > ret = virtnet_send_notf_coal_cmds(vi, ec); > else > ret = virtnet_coal_params_supported(ec); > > ? > > Please also check other nested if/else, usually, too many levels of > nesting is a hint that the logic needs to be optimized. I will optimize this. Thanks! > > Thanks
在 2023/11/22 下午5:29, Yinjun Zhang 写道: > On Mon, 20 Nov 2023 20:37:34 +0800, Heng Qi wrote: > <...> >> @@ -2179,6 +2220,7 @@ static void virtnet_disable_queue_pair(struct virtnet_info *vi, int qp_index) >> virtnet_napi_tx_disable(&vi->sq[qp_index].napi); >> napi_disable(&vi->rq[qp_index].napi); >> xdp_rxq_info_unreg(&vi->rq[qp_index].xdp_rxq); >> + cancel_work_sync(&vi->rq[qp_index].dim.work); > I'm not sure, but please check if here may cause deadlock: > rtnl_lock held -> > .ndo_stop -> > virtnet_disable_queue_pair() -> > cancel_work_sync() -> > virtnet_rx_dim_work() -> > rtnl_lock() Good catch! I tried using cancel_work() which solves the problem. Additionally I tested the scenario of ctrl cmd/.remove/.ndo_stop()/dim_work when there is a lot of concurrency, and this can work very well. Thanks! > >> } >> >> static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index) > <...>
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 69fe09e99b3c..bc32d5aae005 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -19,6 +19,7 @@ #include <linux/average.h> #include <linux/filter.h> #include <linux/kernel.h> +#include <linux/dim.h> #include <net/route.h> #include <net/xdp.h> #include <net/net_failover.h> @@ -172,6 +173,17 @@ struct receive_queue { struct virtnet_rq_stats stats; + /* The number of rx notifications */ + u16 calls; + + /* Is dynamic interrupt moderation enabled? */ + bool dim_enabled; + + /* Dynamic Interrupt Moderation */ + struct dim dim; + + u32 packets_in_napi; + struct virtnet_interrupt_coalesce intr_coal; /* Chain pages by the private ptr. */ @@ -305,6 +317,9 @@ struct virtnet_info { u8 duplex; u32 speed; + /* Is rx dynamic interrupt moderation enabled? */ + bool rx_dim_enabled; + /* Interrupt coalescing settings */ struct virtnet_interrupt_coalesce intr_coal_tx; struct virtnet_interrupt_coalesce intr_coal_rx; @@ -2001,6 +2016,7 @@ static void skb_recv_done(struct virtqueue *rvq) struct virtnet_info *vi = rvq->vdev->priv; struct receive_queue *rq = &vi->rq[vq2rxq(rvq)]; + rq->calls++; virtqueue_napi_schedule(&rq->napi, rvq); } @@ -2141,6 +2157,26 @@ static void virtnet_poll_cleantx(struct receive_queue *rq) } } +static void virtnet_rx_dim_work(struct work_struct *work); + +static void virtnet_rx_dim_update(struct virtnet_info *vi, struct receive_queue *rq) +{ + struct dim_sample cur_sample = {}; + + if (!rq->packets_in_napi) + return; + + u64_stats_update_begin(&rq->stats.syncp); + dim_update_sample(rq->calls, + u64_stats_read(&rq->stats.packets), + u64_stats_read(&rq->stats.bytes), + &cur_sample); + u64_stats_update_end(&rq->stats.syncp); + + net_dim(&rq->dim, cur_sample); + rq->packets_in_napi = 0; +} + static int virtnet_poll(struct napi_struct *napi, int budget) { struct receive_queue *rq = @@ -2149,17 +2185,22 @@ static int virtnet_poll(struct napi_struct *napi, int budget) struct send_queue *sq; unsigned int received; unsigned int xdp_xmit = 0; + bool napi_complete; virtnet_poll_cleantx(rq); received = virtnet_receive(rq, budget, &xdp_xmit); + rq->packets_in_napi += received; if (xdp_xmit & VIRTIO_XDP_REDIR) xdp_do_flush(); /* Out of packets? */ - if (received < budget) - virtqueue_napi_complete(napi, rq->vq, received); + if (received < budget) { + napi_complete = virtqueue_napi_complete(napi, rq->vq, received); + if (napi_complete && rq->dim_enabled) + virtnet_rx_dim_update(vi, rq); + } if (xdp_xmit & VIRTIO_XDP_TX) { sq = virtnet_xdp_get_sq(vi); @@ -2179,6 +2220,7 @@ static void virtnet_disable_queue_pair(struct virtnet_info *vi, int qp_index) virtnet_napi_tx_disable(&vi->sq[qp_index].napi); napi_disable(&vi->rq[qp_index].napi); xdp_rxq_info_unreg(&vi->rq[qp_index].xdp_rxq); + cancel_work_sync(&vi->rq[qp_index].dim.work); } static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index) @@ -2196,6 +2238,9 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index) if (err < 0) goto err_xdp_reg_mem_model; + INIT_WORK(&vi->rq[qp_index].dim.work, virtnet_rx_dim_work); + vi->rq[qp_index].dim.mode = DIM_CQ_PERIOD_MODE_START_FROM_EQE; + virtnet_napi_enable(vi->rq[qp_index].vq, &vi->rq[qp_index].napi); virtnet_napi_tx_enable(vi, vi->sq[qp_index].vq, &vi->sq[qp_index].napi); @@ -2393,8 +2438,10 @@ static int virtnet_rx_resize(struct virtnet_info *vi, qindex = rq - vi->rq; - if (running) + if (running) { napi_disable(&rq->napi); + cancel_work_sync(&rq->dim.work); + } err = virtqueue_resize(rq->vq, ring_num, virtnet_rq_free_unused_buf); if (err) @@ -2403,8 +2450,10 @@ static int virtnet_rx_resize(struct virtnet_info *vi, if (!try_fill_recv(vi, rq, GFP_KERNEL)) schedule_delayed_work(&vi->refill, 0); - if (running) + if (running) { + INIT_WORK(&rq->dim.work, virtnet_rx_dim_work); virtnet_napi_enable(rq->vq, &rq->napi); + } return err; } @@ -3341,24 +3390,55 @@ static int virtnet_send_tx_notf_coal_cmds(struct virtnet_info *vi, static int virtnet_send_rx_notf_coal_cmds(struct virtnet_info *vi, struct ethtool_coalesce *ec) { + bool rx_ctrl_dim_on = !!ec->use_adaptive_rx_coalesce; + bool update = false, switch_dim; struct scatterlist sgs_rx; int i; - vi->ctrl->coal_rx.rx_usecs = cpu_to_le32(ec->rx_coalesce_usecs); - vi->ctrl->coal_rx.rx_max_packets = cpu_to_le32(ec->rx_max_coalesced_frames); - sg_init_one(&sgs_rx, &vi->ctrl->coal_rx, sizeof(vi->ctrl->coal_rx)); - - if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL, - VIRTIO_NET_CTRL_NOTF_COAL_RX_SET, - &sgs_rx)) - return -EINVAL; + switch_dim = rx_ctrl_dim_on != vi->rx_dim_enabled; + if (switch_dim) { + if (rx_ctrl_dim_on) { + if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL)) { + vi->rx_dim_enabled = true; + for (i = 0; i < vi->max_queue_pairs; i++) + vi->rq[i].dim_enabled = true; + } else { + return -EOPNOTSUPP; + } + } else { + vi->rx_dim_enabled = false; + for (i = 0; i < vi->max_queue_pairs; i++) + vi->rq[i].dim_enabled = false; + } + } else { + if (ec->rx_coalesce_usecs != vi->intr_coal_rx.max_usecs || + ec->rx_max_coalesced_frames != vi->intr_coal_rx.max_packets) + update = true; - /* Save parameters */ - vi->intr_coal_rx.max_usecs = ec->rx_coalesce_usecs; - vi->intr_coal_rx.max_packets = ec->rx_max_coalesced_frames; - for (i = 0; i < vi->max_queue_pairs; i++) { - vi->rq[i].intr_coal.max_usecs = ec->rx_coalesce_usecs; - vi->rq[i].intr_coal.max_packets = ec->rx_max_coalesced_frames; + if (vi->rx_dim_enabled) { + if (update) + return -EINVAL; + } else { + /* Since the per-queue coalescing params can be set, + * we need apply the global new params even if they + * are not updated. + */ + vi->ctrl->coal_rx.rx_usecs = cpu_to_le32(ec->rx_coalesce_usecs); + vi->ctrl->coal_rx.rx_max_packets = cpu_to_le32(ec->rx_max_coalesced_frames); + sg_init_one(&sgs_rx, &vi->ctrl->coal_rx, sizeof(vi->ctrl->coal_rx)); + + if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL, + VIRTIO_NET_CTRL_NOTF_COAL_RX_SET, + &sgs_rx)) + return -EINVAL; + + vi->intr_coal_rx.max_usecs = ec->rx_coalesce_usecs; + vi->intr_coal_rx.max_packets = ec->rx_max_coalesced_frames; + for (i = 0; i < vi->max_queue_pairs; i++) { + vi->rq[i].intr_coal.max_usecs = ec->rx_coalesce_usecs; + vi->rq[i].intr_coal.max_packets = ec->rx_max_coalesced_frames; + } + } } return 0; @@ -3380,15 +3460,54 @@ static int virtnet_send_notf_coal_cmds(struct virtnet_info *vi, return 0; } +static int virtnet_send_rx_notf_coal_vq_cmds(struct virtnet_info *vi, + struct ethtool_coalesce *ec, + u16 queue) +{ + bool rx_ctrl_dim_on = !!ec->use_adaptive_rx_coalesce; + bool cur_rx_dim = vi->rq[queue].dim_enabled; + bool update = false, switch_dim; + u32 max_usecs, max_packets; + int err; + + switch_dim = rx_ctrl_dim_on != cur_rx_dim; + if (switch_dim) { + if (rx_ctrl_dim_on) + vi->rq[queue].dim_enabled = true; + else + vi->rq[queue].dim_enabled = false; + } else { + max_usecs = vi->rq[queue].intr_coal.max_usecs; + max_packets = vi->rq[queue].intr_coal.max_packets; + if (ec->rx_coalesce_usecs != max_usecs || + ec->rx_max_coalesced_frames != max_packets) + update = true; + + if (cur_rx_dim) { + if (update) + return -EINVAL; + } else { + if (!update) + return 0; + + err = virtnet_send_rx_ctrl_coal_vq_cmd(vi, queue, + ec->rx_coalesce_usecs, + ec->rx_max_coalesced_frames); + if (err) + return err; + } + } + + return 0; +} + static int virtnet_send_notf_coal_vq_cmds(struct virtnet_info *vi, struct ethtool_coalesce *ec, u16 queue) { int err; - err = virtnet_send_rx_ctrl_coal_vq_cmd(vi, queue, - ec->rx_coalesce_usecs, - ec->rx_max_coalesced_frames); + err = virtnet_send_rx_notf_coal_vq_cmds(vi, ec, queue); if (err) return err; @@ -3401,6 +3520,32 @@ static int virtnet_send_notf_coal_vq_cmds(struct virtnet_info *vi, return 0; } +static void virtnet_rx_dim_work(struct work_struct *work) +{ + struct dim *dim = container_of(work, struct dim, work); + struct receive_queue *rq = container_of(dim, + struct receive_queue, dim); + struct virtnet_info *vi = rq->vq->vdev->priv; + struct net_device *dev = vi->dev; + struct dim_cq_moder update_moder; + int qnum = rq - vi->rq, err; + + update_moder = net_dim_get_rx_moderation(dim->mode, dim->profile_ix); + if (update_moder.usec != vi->rq[qnum].intr_coal.max_usecs || + update_moder.pkts != vi->rq[qnum].intr_coal.max_packets) { + rtnl_lock(); + err = virtnet_send_rx_ctrl_coal_vq_cmd(vi, qnum, + update_moder.usec, + update_moder.pkts); + if (err) + pr_debug("%s: Failed to send dim parameters on rxq%d\n", + dev->name, (int)(rq - vi->rq)); + rtnl_unlock(); + } + + dim->state = DIM_START_MEASURE; +} + static int virtnet_coal_params_supported(struct ethtool_coalesce *ec) { /* usecs coalescing is supported only if VIRTIO_NET_F_NOTF_COAL @@ -3482,6 +3627,7 @@ static int virtnet_get_coalesce(struct net_device *dev, ec->tx_coalesce_usecs = vi->intr_coal_tx.max_usecs; ec->tx_max_coalesced_frames = vi->intr_coal_tx.max_packets; ec->rx_max_coalesced_frames = vi->intr_coal_rx.max_packets; + ec->use_adaptive_rx_coalesce = vi->rx_dim_enabled; } else { ec->rx_max_coalesced_frames = 1; @@ -3539,6 +3685,7 @@ static int virtnet_get_per_queue_coalesce(struct net_device *dev, ec->tx_coalesce_usecs = vi->sq[queue].intr_coal.max_usecs; ec->tx_max_coalesced_frames = vi->sq[queue].intr_coal.max_packets; ec->rx_max_coalesced_frames = vi->rq[queue].intr_coal.max_packets; + ec->use_adaptive_rx_coalesce = vi->rq[queue].dim_enabled; } else { ec->rx_max_coalesced_frames = 1; @@ -3664,7 +3811,7 @@ static int virtnet_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info) static const struct ethtool_ops virtnet_ethtool_ops = { .supported_coalesce_params = ETHTOOL_COALESCE_MAX_FRAMES | - ETHTOOL_COALESCE_USECS, + ETHTOOL_COALESCE_USECS | ETHTOOL_COALESCE_USE_ADAPTIVE_RX, .get_drvinfo = virtnet_get_drvinfo, .get_link = ethtool_op_get_link, .get_ringparam = virtnet_get_ringparam,
By comparing the traffic information in the complete napi processes, let the virtio-net driver automatically adjust the coalescing moderation parameters of each receive queue. Signed-off-by: Heng Qi <hengqi@linux.alibaba.com> --- v2->v3: - Some minor modifications. v1->v2: - Improved the judgment of dim switch conditions. - Cancel the work when vq reset. drivers/net/virtio_net.c | 191 ++++++++++++++++++++++++++++++++++----- 1 file changed, 169 insertions(+), 22 deletions(-)