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Date: Mon, 26 Mar 2018 14:36:02 -0700
From: Florian Fainelli <f.fainelli@...il.com>
To: Tal Gilboa <talgi@...lanox.com>, netdev@...r.kernel.org
Cc: davem@...emloft.net, jaedon.shin@...il.com, pgynther@...gle.com,
opendmb@...il.com, michal.chan@...adcom.com, gospo@...adcom.com,
saeedm@...lanox.com
Subject: Re: [PATCH net-next 1/2] net: systemport: Implement adaptive
interrupt coalescing
On 03/26/2018 02:22 PM, Tal Gilboa wrote:
> On 3/23/2018 4:19 AM, Florian Fainelli wrote:
>> Implement support for adaptive RX and TX interrupt coalescing using
>> net_dim. We have each of our TX ring and our single RX ring implement a
>> bcm_sysport_net_dim structure which holds an interrupt counter, number
>> of packets, bytes, and a container for a net_dim instance.
>>
>> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
>> ---
>> drivers/net/ethernet/broadcom/bcmsysport.c | 141
>> ++++++++++++++++++++++++++---
>> drivers/net/ethernet/broadcom/bcmsysport.h | 14 +++
>> 2 files changed, 140 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/broadcom/bcmsysport.c
>> b/drivers/net/ethernet/broadcom/bcmsysport.c
>> index f15a8fc6dfc9..5a5a726bafa4 100644
>> --- a/drivers/net/ethernet/broadcom/bcmsysport.c
>> +++ b/drivers/net/ethernet/broadcom/bcmsysport.c
>> @@ -15,6 +15,7 @@
>> #include <linux/module.h>
>> #include <linux/kernel.h>
>> #include <linux/netdevice.h>
>> +#include <linux/net_dim.h>
>
> I don't think you need this include. You already include net_dim in
> bcmsysport.h and include the bcmsysport.h here.
Indeed.
>
>> #include <linux/etherdevice.h>
>> #include <linux/platform_device.h>
>> #include <linux/of.h>
>> @@ -574,21 +575,55 @@ static int bcm_sysport_set_wol(struct net_device
>> *dev,
>> return 0;
>> }
>> +static void bcm_sysport_set_rx_coalesce(struct bcm_sysport_priv *priv)
>> +{
>> + u32 reg;
>> +
>> + reg = rdma_readl(priv, RDMA_MBDONE_INTR);
>> + reg &= ~(RDMA_INTR_THRESH_MASK |
>> + RDMA_TIMEOUT_MASK << RDMA_TIMEOUT_SHIFT);
>> + reg |= priv->dim.coal_pkts;
>> + reg |= DIV_ROUND_UP(priv->dim.coal_usecs * 1000, 8192) <<
>> + RDMA_TIMEOUT_SHIFT;
>> + rdma_writel(priv, reg, RDMA_MBDONE_INTR);
>> +}
>> +
>> +static void bcm_sysport_set_tx_coalesce(struct bcm_sysport_tx_ring
>> *ring)
>> +{
>> + struct bcm_sysport_priv *priv = ring->priv;
>> + u32 reg;
>> +
>> + reg = tdma_readl(priv, TDMA_DESC_RING_INTR_CONTROL(ring->index));
>> + reg &= ~(RING_INTR_THRESH_MASK |
>> + RING_TIMEOUT_MASK << RING_TIMEOUT_SHIFT);
>> + reg |= ring->dim.coal_pkts;
>> + reg |= DIV_ROUND_UP(ring->dim.coal_usecs * 1000, 8192) <<
>> + RING_TIMEOUT_SHIFT;
>> + tdma_writel(priv, reg, TDMA_DESC_RING_INTR_CONTROL(ring->index));
>> +}
>> +
>
> I wouldn't couple these functions with dim. This implies dim is always
> used. IMO, would be more clear to use a generic method which takes usecs
> and packets as an argument.
I did not want to create an additional structure for storing coalescing
parameters, but if you prefer I make this function take two parameters,
that sounds entirely reasonable.
>
>> static int bcm_sysport_get_coalesce(struct net_device *dev,
>> struct ethtool_coalesce *ec)
>> {
>> struct bcm_sysport_priv *priv = netdev_priv(dev);
>> + struct bcm_sysport_tx_ring *ring;
>> + unsigned int i;
>> u32 reg;
>> reg = tdma_readl(priv, TDMA_DESC_RING_INTR_CONTROL(0));
>> ec->tx_coalesce_usecs = (reg >> RING_TIMEOUT_SHIFT) * 8192 /
>> 1000;
>> ec->tx_max_coalesced_frames = reg & RING_INTR_THRESH_MASK;
>> + for (i = 0; i < dev->num_tx_queues; i++) {
>> + ring = &priv->tx_rings[i];
>> + ec->use_adaptive_tx_coalesce |= ring->dim.use_dim;
>> + }
>> reg = rdma_readl(priv, RDMA_MBDONE_INTR);
>> ec->rx_coalesce_usecs = (reg >> RDMA_TIMEOUT_SHIFT) * 8192 /
>> 1000;
>> ec->rx_max_coalesced_frames = reg & RDMA_INTR_THRESH_MASK;
>> + ec->use_adaptive_rx_coalesce = priv->dim.use_dim;
>> return 0;
>> }
>> @@ -597,8 +632,8 @@ static int bcm_sysport_set_coalesce(struct
>> net_device *dev,
>> struct ethtool_coalesce *ec)
>> {
>> struct bcm_sysport_priv *priv = netdev_priv(dev);
>> + struct bcm_sysport_tx_ring *ring;
>> unsigned int i;
>> - u32 reg;
>> /* Base system clock is 125Mhz, DMA timeout is this reference
>> clock
>> * divided by 1024, which yield roughly 8.192 us, our maximum
>> value has
>> @@ -615,22 +650,26 @@ static int bcm_sysport_set_coalesce(struct
>> net_device *dev,
>> return -EINVAL;
>> for (i = 0; i < dev->num_tx_queues; i++) {
>> - reg = tdma_readl(priv, TDMA_DESC_RING_INTR_CONTROL(i));
>> - reg &= ~(RING_INTR_THRESH_MASK |
>> - RING_TIMEOUT_MASK << RING_TIMEOUT_SHIFT);
>> - reg |= ec->tx_max_coalesced_frames;
>> - reg |= DIV_ROUND_UP(ec->tx_coalesce_usecs * 1000, 8192) <<
>> - RING_TIMEOUT_SHIFT;
>> - tdma_writel(priv, reg, TDMA_DESC_RING_INTR_CONTROL(i));
>> + ring = &priv->tx_rings[i];
>> + ring->dim.coal_pkts = ec->tx_max_coalesced_frames;
>> + ring->dim.coal_usecs = ec->tx_coalesce_usecs;
>> + if (!ec->use_adaptive_tx_coalesce && ring->dim.use_dim) {
>> + ring->dim.coal_pkts = 1;
>> + ring->dim.coal_usecs = 0;
>> + }
>> + ring->dim.use_dim = ec->use_adaptive_tx_coalesce;
>> + bcm_sysport_set_tx_coalesce(ring);
>> }
>
> If I understand correctly, if I disable dim, moderation is set to
> {usecs,packets}={0,1} regardless of the input from ethtool right?
Correct, these are the default coalescing parameters that the driver
sets. As mentioned before, since I am not storing any coalescing
parameters other than these two, there is no copy of what an user might
have previously provided, falling back to the defaults seemed reasonable.
> Doesn't this break the wanted behavior? As mentioned above, I would
> decouple dim from the set_tx/rx_coalesce() function. Also, when dim is
> enabled, why change dim.coal_pkts/usecs? They would just be overwritten
> in the next iteration of net_dim.
Indeed, that is not necessary.
>
>> - reg = rdma_readl(priv, RDMA_MBDONE_INTR);
>> - reg &= ~(RDMA_INTR_THRESH_MASK |
>> - RDMA_TIMEOUT_MASK << RDMA_TIMEOUT_SHIFT);
>> - reg |= ec->rx_max_coalesced_frames;
>> - reg |= DIV_ROUND_UP(ec->rx_coalesce_usecs * 1000, 8192) <<
>> - RDMA_TIMEOUT_SHIFT;
>> - rdma_writel(priv, reg, RDMA_MBDONE_INTR);
>> + priv->dim.coal_usecs = ec->rx_coalesce_usecs;
>> + priv->dim.coal_pkts = ec->rx_max_coalesced_frames;
>> +
>> + if (!ec->use_adaptive_rx_coalesce && priv->dim.use_dim) {
>> + priv->dim.coal_pkts = 1;
>> + priv->dim.coal_usecs = 0;
>> + }
>> + priv->dim.use_dim = ec->use_adaptive_rx_coalesce;
>> + bcm_sysport_set_rx_coalesce(priv);
>
> Same comment as above.
>
>> return 0;
>> }
>> @@ -709,6 +748,7 @@ static unsigned int bcm_sysport_desc_rx(struct
>> bcm_sysport_priv *priv,
>> struct bcm_sysport_stats64 *stats64 = &priv->stats64;
>> struct net_device *ndev = priv->netdev;
>> unsigned int processed = 0, to_process;
>> + unsigned int processed_bytes = 0;
>> struct bcm_sysport_cb *cb;
>> struct sk_buff *skb;
>> unsigned int p_index;
>> @@ -800,6 +840,7 @@ static unsigned int bcm_sysport_desc_rx(struct
>> bcm_sysport_priv *priv,
>> */
>> skb_pull(skb, sizeof(*rsb) + 2);
>> len -= (sizeof(*rsb) + 2);
>> + processed_bytes += len;
>> /* UniMAC may forward CRC */
>> if (priv->crc_fwd) {
>> @@ -824,6 +865,9 @@ static unsigned int bcm_sysport_desc_rx(struct
>> bcm_sysport_priv *priv,
>> priv->rx_read_ptr = 0;
>> }
>> + priv->dim.packets = processed;
>> + priv->dim.bytes = processed_bytes;
>> +
>> return processed;
>> }
>> @@ -900,6 +944,8 @@ static unsigned int
>> __bcm_sysport_tx_reclaim(struct bcm_sysport_priv *priv,
>> ring->packets += pkts_compl;
>> ring->bytes += bytes_compl;
>> u64_stats_update_end(&priv->syncp);
>> + ring->dim.packets = pkts_compl;
>> + ring->dim.bytes = bytes_compl;
>> ring->c_index = c_index;
>> @@ -945,6 +991,7 @@ static int bcm_sysport_tx_poll(struct
>> napi_struct *napi, int budget)
>> {
>> struct bcm_sysport_tx_ring *ring =
>> container_of(napi, struct bcm_sysport_tx_ring, napi);
>> + struct net_dim_sample dim_sample;
>> unsigned int work_done = 0;
>> work_done = bcm_sysport_tx_reclaim(ring->priv, ring);
>> @@ -961,6 +1008,12 @@ static int bcm_sysport_tx_poll(struct
>> napi_struct *napi, int budget)
>> return 0;
>> }
>> + if (ring->dim.use_dim) {
>> + net_dim_sample(ring->dim.event_ctr, ring->dim.packets,
>> + ring->dim.bytes, &dim_sample);
>> + net_dim(&ring->dim.dim, dim_sample);
>> + }
>> +
>> return budget;
>> }
>> @@ -976,6 +1029,7 @@ static int bcm_sysport_poll(struct napi_struct
>> *napi, int budget)
>> {
>> struct bcm_sysport_priv *priv =
>> container_of(napi, struct bcm_sysport_priv, napi);
>> + struct net_dim_sample dim_sample;
>> unsigned int work_done = 0;
>> work_done = bcm_sysport_desc_rx(priv, budget);
>> @@ -998,6 +1052,12 @@ static int bcm_sysport_poll(struct napi_struct
>> *napi, int budget)
>> intrl2_0_mask_clear(priv, INTRL2_0_RDMA_MBDONE);
>> }
>> + if (priv->dim.use_dim) {
>> + net_dim_sample(priv->dim.event_ctr, priv->dim.packets,
>> + priv->dim.bytes, &dim_sample);
>> + net_dim(&priv->dim.dim, dim_sample);
>> + }
>> +
>> return work_done;
>> }
>> @@ -1016,6 +1076,40 @@ static void
>> bcm_sysport_resume_from_wol(struct bcm_sysport_priv *priv)
>> netif_dbg(priv, wol, priv->netdev, "resumed from WOL\n");
>> }
>> +static void bcm_sysport_dim_work(struct work_struct *work)
>> +{
>> + struct net_dim *dim = container_of(work, struct net_dim, work);
>> + struct bcm_sysport_net_dim *ndim =
>> + container_of(dim, struct bcm_sysport_net_dim, dim);
>> + struct bcm_sysport_priv *priv =
>> + container_of(ndim, struct bcm_sysport_priv, dim);
>> + struct net_dim_cq_moder cur_profile =
>> + net_dim_get_profile(dim->mode, dim->profile_ix);
>> +
>> + priv->dim.coal_usecs = cur_profile.usec;
>> + priv->dim.coal_pkts = cur_profile.pkts;
>> +
>> + bcm_sysport_set_rx_coalesce(priv);
>> + dim->state = NET_DIM_START_MEASURE;
>> +}
>> +
>> +static void bcm_sysport_dim_tx_work(struct work_struct *work)
>> +{
>> + struct net_dim *dim = container_of(work, struct net_dim, work);
>> + struct bcm_sysport_net_dim *ndim =
>> + container_of(dim, struct bcm_sysport_net_dim, dim);
>> + struct bcm_sysport_tx_ring *ring =
>> + container_of(ndim, struct bcm_sysport_tx_ring, dim);
>> + struct net_dim_cq_moder cur_profile =
>> + net_dim_get_profile(dim->mode, dim->profile_ix);
>> +
>> + ring->dim.coal_usecs = cur_profile.usec;
>> + ring->dim.coal_pkts = cur_profile.pkts;
>> +
>> + bcm_sysport_set_tx_coalesce(ring);
>> + dim->state = NET_DIM_START_MEASURE;
>> +}
>> +
>> /* RX and misc interrupt routine */
>> static irqreturn_t bcm_sysport_rx_isr(int irq, void *dev_id)
>> {
>> @@ -1034,6 +1128,7 @@ static irqreturn_t bcm_sysport_rx_isr(int irq,
>> void *dev_id)
>> }
>> if (priv->irq0_stat & INTRL2_0_RDMA_MBDONE) {
>> + priv->dim.event_ctr++;
>> if (likely(napi_schedule_prep(&priv->napi))) {
>> /* disable RX interrupts */
>> intrl2_0_mask_set(priv, INTRL2_0_RDMA_MBDONE);
>> @@ -1061,6 +1156,7 @@ static irqreturn_t bcm_sysport_rx_isr(int irq,
>> void *dev_id)
>> continue;
>> txr = &priv->tx_rings[ring];
>> + txr->dim.event_ctr++;
>> if (likely(napi_schedule_prep(&txr->napi))) {
>> intrl2_0_mask_set(priv, ring_bit);
>> @@ -1093,6 +1189,7 @@ static irqreturn_t bcm_sysport_tx_isr(int irq,
>> void *dev_id)
>> continue;
>> txr = &priv->tx_rings[ring];
>> + txr->dim.event_ctr++;
>> if (likely(napi_schedule_prep(&txr->napi))) {
>> intrl2_1_mask_set(priv, BIT(ring));
>> @@ -1358,6 +1455,16 @@ static void bcm_sysport_adj_link(struct
>> net_device *dev)
>> phy_print_status(phydev);
>> }
>> +static void bcm_sysport_init_dim(struct bcm_sysport_net_dim *dim,
>> + void (*cb)(struct work_struct *work))
>> +{
>> + INIT_WORK(&dim->dim.work, cb);
>> + dim->dim.mode = NET_DIM_CQ_PERIOD_MODE_START_FROM_EQE;
>> + dim->event_ctr = 0;
>> + dim->packets = 0;
>> + dim->bytes = 0;
>> +}
>
> What about default values for coal_usecs/pkts? dim supports it through
> net_dim_get_def_profile(mode) function.
OK, thanks I did not know that.
--
Florian
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