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igb: Improve multiqueue AIM support
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Improve multiqueue performance
Change itr_val to reflect ITR timer value instead of ints/sec
Cleaned up AIM algorithms in general

Based on work by Mitch Williams

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Acked-by: Mitch Williams <mitch.a.williams@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
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Alexander Duyck authored and Jeff Garzik committed Jul 11, 2008
1 parent 9280fa5 commit 6eb5a7f
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Showing 3 changed files with 113 additions and 81 deletions.
8 changes: 5 additions & 3 deletions drivers/net/igb/igb.h
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Original file line number Diff line number Diff line change
Expand Up @@ -47,7 +47,9 @@ struct igb_adapter;

#define IGB_MIN_DYN_ITR 3000
#define IGB_MAX_DYN_ITR 96000
#define IGB_START_ITR 6000

/* ((1000000000ns / (6000ints/s * 1024ns)) << 2 = 648 */
#define IGB_START_ITR 648

#define IGB_DYN_ITR_PACKET_THRESHOLD 2
#define IGB_DYN_ITR_LENGTH_LOW 200
Expand Down Expand Up @@ -170,9 +172,10 @@ struct igb_ring {
};
/* RX */
struct {
int no_itr_adjust;
struct igb_queue_stats rx_stats;
struct napi_struct napi;
int set_itr;
struct igb_ring *buddy;
#ifdef CONFIG_IGB_LRO
struct net_lro_mgr lro_mgr;
bool lro_used;
Expand Down Expand Up @@ -219,7 +222,6 @@ struct igb_adapter {
u32 itr_setting;
u16 tx_itr;
u16 rx_itr;
int set_itr;

struct work_struct reset_task;
struct work_struct watchdog_task;
Expand Down
17 changes: 11 additions & 6 deletions drivers/net/igb/igb_ethtool.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1861,6 +1861,8 @@ static int igb_set_coalesce(struct net_device *netdev,
struct ethtool_coalesce *ec)
{
struct igb_adapter *adapter = netdev_priv(netdev);
struct e1000_hw *hw = &adapter->hw;
int i;

if ((ec->rx_coalesce_usecs > IGB_MAX_ITR_USECS) ||
((ec->rx_coalesce_usecs > 3) &&
Expand All @@ -1869,13 +1871,16 @@ static int igb_set_coalesce(struct net_device *netdev,
return -EINVAL;

/* convert to rate of irq's per second */
if (ec->rx_coalesce_usecs <= 3)
if (ec->rx_coalesce_usecs && ec->rx_coalesce_usecs <= 3) {
adapter->itr_setting = ec->rx_coalesce_usecs;
else
adapter->itr_setting = (1000000 / ec->rx_coalesce_usecs);
adapter->itr = IGB_START_ITR;
} else {
adapter->itr_setting = ec->rx_coalesce_usecs << 2;
adapter->itr = adapter->itr_setting;
}

if (netif_running(netdev))
igb_reinit_locked(adapter);
for (i = 0; i < adapter->num_rx_queues; i++)
wr32(adapter->rx_ring[i].itr_register, adapter->itr);

return 0;
}
Expand All @@ -1888,7 +1893,7 @@ static int igb_get_coalesce(struct net_device *netdev,
if (adapter->itr_setting <= 3)
ec->rx_coalesce_usecs = adapter->itr_setting;
else
ec->rx_coalesce_usecs = 1000000 / adapter->itr_setting;
ec->rx_coalesce_usecs = adapter->itr_setting >> 2;

return 0;
}
Expand Down
169 changes: 97 additions & 72 deletions drivers/net/igb/igb_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -255,6 +255,8 @@ static int igb_alloc_queues(struct igb_adapter *adapter)
return -ENOMEM;
}

adapter->rx_ring->buddy = adapter->tx_ring;

for (i = 0; i < adapter->num_tx_queues; i++) {
struct igb_ring *ring = &(adapter->tx_ring[i]);
ring->adapter = adapter;
Expand Down Expand Up @@ -375,18 +377,19 @@ static void igb_configure_msix(struct igb_adapter *adapter)
igb_assign_vector(adapter, IGB_N0_QUEUE, i, vector++);
adapter->eims_enable_mask |= tx_ring->eims_value;
if (tx_ring->itr_val)
writel(1000000000 / (tx_ring->itr_val * 256),
writel(tx_ring->itr_val,
hw->hw_addr + tx_ring->itr_register);
else
writel(1, hw->hw_addr + tx_ring->itr_register);
}

for (i = 0; i < adapter->num_rx_queues; i++) {
struct igb_ring *rx_ring = &adapter->rx_ring[i];
rx_ring->buddy = 0;
igb_assign_vector(adapter, i, IGB_N0_QUEUE, vector++);
adapter->eims_enable_mask |= rx_ring->eims_value;
if (rx_ring->itr_val)
writel(1000000000 / (rx_ring->itr_val * 256),
writel(rx_ring->itr_val,
hw->hw_addr + rx_ring->itr_register);
else
writel(1, hw->hw_addr + rx_ring->itr_register);
Expand Down Expand Up @@ -449,7 +452,7 @@ static int igb_request_msix(struct igb_adapter *adapter)
if (err)
goto out;
ring->itr_register = E1000_EITR(0) + (vector << 2);
ring->itr_val = adapter->itr;
ring->itr_val = 976; /* ~4000 ints/sec */
vector++;
}
for (i = 0; i < adapter->num_rx_queues; i++) {
Expand Down Expand Up @@ -1898,8 +1901,7 @@ static void igb_configure_rx(struct igb_adapter *adapter)
mdelay(10);

if (adapter->itr_setting > 3)
wr32(E1000_ITR,
1000000000 / (adapter->itr * 256));
wr32(E1000_ITR, adapter->itr);

/* Setup the HW Rx Head and Tail Descriptor Pointers and
* the Base and Length of the Rx Descriptor Ring */
Expand Down Expand Up @@ -2463,38 +2465,60 @@ enum latency_range {
};


static void igb_lower_rx_eitr(struct igb_adapter *adapter,
struct igb_ring *rx_ring)
/**
* igb_update_ring_itr - update the dynamic ITR value based on packet size
*
* Stores a new ITR value based on strictly on packet size. This
* algorithm is less sophisticated than that used in igb_update_itr,
* due to the difficulty of synchronizing statistics across multiple
* receive rings. The divisors and thresholds used by this fuction
* were determined based on theoretical maximum wire speed and testing
* data, in order to minimize response time while increasing bulk
* throughput.
* This functionality is controlled by the InterruptThrottleRate module
* parameter (see igb_param.c)
* NOTE: This function is called only when operating in a multiqueue
* receive environment.
* @rx_ring: pointer to ring
**/
static void igb_update_ring_itr(struct igb_ring *rx_ring)
{
struct e1000_hw *hw = &adapter->hw;
int new_val;
int new_val = rx_ring->itr_val;
int avg_wire_size = 0;
struct igb_adapter *adapter = rx_ring->adapter;

new_val = rx_ring->itr_val / 2;
if (new_val < IGB_MIN_DYN_ITR)
new_val = IGB_MIN_DYN_ITR;
if (!rx_ring->total_packets)
goto clear_counts; /* no packets, so don't do anything */

if (new_val != rx_ring->itr_val) {
rx_ring->itr_val = new_val;
wr32(rx_ring->itr_register,
1000000000 / (new_val * 256));
/* For non-gigabit speeds, just fix the interrupt rate at 4000
* ints/sec - ITR timer value of 120 ticks.
*/
if (adapter->link_speed != SPEED_1000) {
new_val = 120;
goto set_itr_val;
}
}
avg_wire_size = rx_ring->total_bytes / rx_ring->total_packets;

static void igb_raise_rx_eitr(struct igb_adapter *adapter,
struct igb_ring *rx_ring)
{
struct e1000_hw *hw = &adapter->hw;
int new_val;
/* Add 24 bytes to size to account for CRC, preamble, and gap */
avg_wire_size += 24;

/* Don't starve jumbo frames */
avg_wire_size = min(avg_wire_size, 3000);

new_val = rx_ring->itr_val * 2;
if (new_val > IGB_MAX_DYN_ITR)
new_val = IGB_MAX_DYN_ITR;
/* Give a little boost to mid-size frames */
if ((avg_wire_size > 300) && (avg_wire_size < 1200))
new_val = avg_wire_size / 3;
else
new_val = avg_wire_size / 2;

set_itr_val:
if (new_val != rx_ring->itr_val) {
rx_ring->itr_val = new_val;
wr32(rx_ring->itr_register,
1000000000 / (new_val * 256));
rx_ring->set_itr = 1;
}
clear_counts:
rx_ring->total_bytes = 0;
rx_ring->total_packets = 0;
}

/**
Expand Down Expand Up @@ -2561,8 +2585,7 @@ static unsigned int igb_update_itr(struct igb_adapter *adapter, u16 itr_setting,
return retval;
}

static void igb_set_itr(struct igb_adapter *adapter, u16 itr_register,
int rx_only)
static void igb_set_itr(struct igb_adapter *adapter)
{
u16 current_itr;
u32 new_itr = adapter->itr;
Expand All @@ -2578,26 +2601,23 @@ static void igb_set_itr(struct igb_adapter *adapter, u16 itr_register,
adapter->rx_itr,
adapter->rx_ring->total_packets,
adapter->rx_ring->total_bytes);
/* conservative mode (itr 3) eliminates the lowest_latency setting */
if (adapter->itr_setting == 3 && adapter->rx_itr == lowest_latency)
adapter->rx_itr = low_latency;

if (!rx_only) {
if (adapter->rx_ring->buddy) {
adapter->tx_itr = igb_update_itr(adapter,
adapter->tx_itr,
adapter->tx_ring->total_packets,
adapter->tx_ring->total_bytes);
/* conservative mode (itr 3) eliminates the
* lowest_latency setting */
if (adapter->itr_setting == 3 &&
adapter->tx_itr == lowest_latency)
adapter->tx_itr = low_latency;

current_itr = max(adapter->rx_itr, adapter->tx_itr);
} else {
current_itr = adapter->rx_itr;
}

/* conservative mode (itr 3) eliminates the lowest_latency setting */
if (adapter->itr_setting == 3 &&
current_itr == lowest_latency)
current_itr = low_latency;

switch (current_itr) {
/* counts and packets in update_itr are dependent on these numbers */
case lowest_latency:
Expand All @@ -2614,6 +2634,13 @@ static void igb_set_itr(struct igb_adapter *adapter, u16 itr_register,
}

set_itr_now:
adapter->rx_ring->total_bytes = 0;
adapter->rx_ring->total_packets = 0;
if (adapter->rx_ring->buddy) {
adapter->rx_ring->buddy->total_bytes = 0;
adapter->rx_ring->buddy->total_packets = 0;
}

if (new_itr != adapter->itr) {
/* this attempts to bias the interrupt rate towards Bulk
* by adding intermediate steps when interrupt rate is
Expand All @@ -2628,7 +2655,8 @@ static void igb_set_itr(struct igb_adapter *adapter, u16 itr_register,
* ends up being correct.
*/
adapter->itr = new_itr;
adapter->set_itr = 1;
adapter->rx_ring->itr_val = 1000000000 / (new_itr * 256);
adapter->rx_ring->set_itr = 1;
}

return;
Expand Down Expand Up @@ -2979,6 +3007,7 @@ static int igb_xmit_frame_ring_adv(struct sk_buff *skb,
/* this is a hard error */
return NETDEV_TX_BUSY;
}
skb_orphan(skb);

if (adapter->vlgrp && vlan_tx_tag_present(skb)) {
tx_flags |= IGB_TX_FLAGS_VLAN;
Expand Down Expand Up @@ -3312,8 +3341,6 @@ static irqreturn_t igb_msix_tx(int irq, void *data)
struct igb_adapter *adapter = tx_ring->adapter;
struct e1000_hw *hw = &adapter->hw;

if (!tx_ring->itr_val)
wr32(E1000_EIMC, tx_ring->eims_value);
#ifdef CONFIG_DCA
if (adapter->flags & IGB_FLAG_DCA_ENABLED)
igb_update_tx_dca(tx_ring);
Expand All @@ -3332,21 +3359,36 @@ static irqreturn_t igb_msix_tx(int irq, void *data)
return IRQ_HANDLED;
}

static void igb_write_itr(struct igb_ring *ring)
{
struct e1000_hw *hw = &ring->adapter->hw;
if ((ring->adapter->itr_setting & 3) && ring->set_itr) {
switch (hw->mac.type) {
case e1000_82576:
wr32(ring->itr_register,
ring->itr_val |
0x80000000);
break;
default:
wr32(ring->itr_register,
ring->itr_val |
(ring->itr_val << 16));
break;
}
ring->set_itr = 0;
}
}

static irqreturn_t igb_msix_rx(int irq, void *data)
{
struct igb_ring *rx_ring = data;
struct igb_adapter *adapter = rx_ring->adapter;
struct e1000_hw *hw = &adapter->hw;

/* Write the ITR value calculated at the end of the
* previous interrupt.
*/

if (adapter->set_itr) {
wr32(rx_ring->itr_register,
1000000000 / (rx_ring->itr_val * 256));
adapter->set_itr = 0;
}
igb_write_itr(rx_ring);

if (netif_rx_schedule_prep(adapter->netdev, &rx_ring->napi))
__netif_rx_schedule(adapter->netdev, &rx_ring->napi);
Expand Down Expand Up @@ -3493,13 +3535,7 @@ static irqreturn_t igb_intr_msi(int irq, void *data)
/* read ICR disables interrupts using IAM */
u32 icr = rd32(E1000_ICR);

/* Write the ITR value calculated at the end of the
* previous interrupt.
*/
if (adapter->set_itr) {
wr32(E1000_ITR, 1000000000 / (adapter->itr * 256));
adapter->set_itr = 0;
}
igb_write_itr(adapter->rx_ring);

if (icr & (E1000_ICR_RXSEQ | E1000_ICR_LSC)) {
hw->mac.get_link_status = 1;
Expand Down Expand Up @@ -3529,13 +3565,7 @@ static irqreturn_t igb_intr(int irq, void *data)
if (!icr)
return IRQ_NONE; /* Not our interrupt */

/* Write the ITR value calculated at the end of the
* previous interrupt.
*/
if (adapter->set_itr) {
wr32(E1000_ITR, 1000000000 / (adapter->itr * 256));
adapter->set_itr = 0;
}
igb_write_itr(adapter->rx_ring);

/* IMS will not auto-mask if INT_ASSERTED is not set, and if it is
* not set, then the adapter didn't send an interrupt */
Expand Down Expand Up @@ -3585,7 +3615,7 @@ static int igb_poll(struct napi_struct *napi, int budget)
if ((tx_clean_complete && (work_done < budget)) ||
!netif_running(netdev)) {
if (adapter->itr_setting & 3)
igb_set_itr(adapter, E1000_ITR, false);
igb_set_itr(adapter);
netif_rx_complete(netdev, napi);
if (!test_bit(__IGB_DOWN, &adapter->state))
igb_irq_enable(adapter);
Expand Down Expand Up @@ -3619,15 +3649,11 @@ static int igb_clean_rx_ring_msix(struct napi_struct *napi, int budget)
quit_polling:
netif_rx_complete(netdev, napi);

wr32(E1000_EIMS, rx_ring->eims_value);
if ((adapter->itr_setting & 3) && !rx_ring->no_itr_adjust &&
(rx_ring->total_packets > IGB_DYN_ITR_PACKET_THRESHOLD)) {
int mean_size = rx_ring->total_bytes /
rx_ring->total_packets;
if (mean_size < IGB_DYN_ITR_LENGTH_LOW)
igb_raise_rx_eitr(adapter, rx_ring);
else if (mean_size > IGB_DYN_ITR_LENGTH_HIGH)
igb_lower_rx_eitr(adapter, rx_ring);
if (adapter->itr_setting & 3) {
if (adapter->num_rx_queues == 1)
igb_set_itr(adapter);
else
igb_update_ring_itr(rx_ring);
}

if (!test_bit(__IGB_DOWN, &adapter->state))
Expand Down Expand Up @@ -3972,7 +3998,6 @@ static bool igb_clean_rx_irq_adv(struct igb_ring *rx_ring,
dev_kfree_skb_irq(skb);
goto next_desc;
}
rx_ring->no_itr_adjust |= (staterr & E1000_RXD_STAT_DYNINT);

total_bytes += skb->len;
total_packets++;
Expand Down

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