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Message-Id: <1445294971-44714-10-git-send-email-jeffrey.t.kirsher@intel.com>
Date: Mon, 19 Oct 2015 15:49:23 -0700
From: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To: davem@...emloft.net
Cc: Jesse Brandeburg <jesse.brandeburg@...el.com>,
netdev@...r.kernel.org, nhorman@...hat.com, sassmann@...hat.com,
jogreene@...hat.com, Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Subject: [net-next v2 09/17] i40e/i40evf: adjust interrupt throttle less frequently
From: Jesse Brandeburg <jesse.brandeburg@...el.com>
The adaptive ITR (interrupt throttle rate) algorithm was adjusting
the hardware's interrupt rate too frequently. This caused a lot
of variation in the interrupt rate for fairly constant workloads.
Change the code to have a counter and adjust only once every N
number of interrupts.
Change-ID: I0460f1f86571037484eca5aca36ac4d889cb8389
Signed-off-by: Jesse Brandeburg <jesse.brandeburg@...el.com>
Tested-by: Andrew Bowers <andrewx.bowers@...el.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
drivers/net/ethernet/intel/i40e/i40e.h | 2 ++
drivers/net/ethernet/intel/i40e/i40e_main.c | 2 ++
drivers/net/ethernet/intel/i40e/i40e_txrx.c | 22 ++++++++++++++++++++--
drivers/net/ethernet/intel/i40e/i40e_txrx.h | 4 ++--
drivers/net/ethernet/intel/i40evf/i40e_txrx.c | 23 +++++++++++++++++++++--
drivers/net/ethernet/intel/i40evf/i40e_txrx.h | 4 ++--
drivers/net/ethernet/intel/i40evf/i40evf.h | 2 ++
drivers/net/ethernet/intel/i40evf/i40evf_main.c | 2 ++
8 files changed, 53 insertions(+), 8 deletions(-)
diff --git a/drivers/net/ethernet/intel/i40e/i40e.h b/drivers/net/ethernet/intel/i40e/i40e.h
index b7818be..7c2b2e8 100644
--- a/drivers/net/ethernet/intel/i40e/i40e.h
+++ b/drivers/net/ethernet/intel/i40e/i40e.h
@@ -577,6 +577,8 @@ struct i40e_q_vector {
struct rcu_head rcu; /* to avoid race with update stats on free */
char name[I40E_INT_NAME_STR_LEN];
bool arm_wb_state;
+#define ITR_COUNTDOWN_START 100
+ u8 itr_countdown; /* when 0 should adjust ITR */
} ____cacheline_internodealigned_in_smp;
/* lan device */
diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 7d52092..e0142de 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -3087,6 +3087,7 @@ static void i40e_vsi_configure_msix(struct i40e_vsi *vsi)
for (i = 0; i < vsi->num_q_vectors; i++, vector++) {
struct i40e_q_vector *q_vector = vsi->q_vectors[i];
+ q_vector->itr_countdown = ITR_COUNTDOWN_START;
q_vector->rx.itr = ITR_TO_REG(vsi->rx_itr_setting);
q_vector->rx.latency_range = I40E_LOW_LATENCY;
wr32(hw, I40E_PFINT_ITRN(I40E_RX_ITR, vector - 1),
@@ -3182,6 +3183,7 @@ static void i40e_configure_msi_and_legacy(struct i40e_vsi *vsi)
u32 val;
/* set the ITR configuration */
+ q_vector->itr_countdown = ITR_COUNTDOWN_START;
q_vector->rx.itr = ITR_TO_REG(vsi->rx_itr_setting);
q_vector->rx.latency_range = I40E_LOW_LATENCY;
wr32(hw, I40E_PFINT_ITR0(I40E_RX_ITR), q_vector->rx.itr);
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 7aea143..006f0fb 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -845,10 +845,12 @@ static bool i40e_set_new_dynamic_itr(struct i40e_ring_container *rc)
* The math works out because the divisor is in 10^(-6) which
* turns the bytes/us input value into MB/s values, but
* make sure to use usecs, as the register values written
- * are in 2 usec increments in the ITR registers.
+ * are in 2 usec increments in the ITR registers, and make sure
+ * to use the smoothed values that the countdown timer gives us.
*/
- usecs = (rc->itr << 1);
+ usecs = (rc->itr << 1) * ITR_COUNTDOWN_START;
bytes_per_int = rc->total_bytes / usecs;
+
switch (new_latency_range) {
case I40E_LOWEST_LATENCY:
if (bytes_per_int > 10)
@@ -1806,8 +1808,17 @@ static inline void i40e_update_enable_itr(struct i40e_vsi *vsi,
vector = (q_vector->v_idx + vsi->base_vector);
+ /* avoid dynamic calculation if in countdown mode OR if
+ * all dynamic is disabled
+ */
rxval = txval = i40e_buildreg_itr(I40E_ITR_NONE, 0);
+ if (q_vector->itr_countdown > 0 ||
+ (!ITR_IS_DYNAMIC(vsi->rx_itr_setting) &&
+ !ITR_IS_DYNAMIC(vsi->tx_itr_setting))) {
+ goto enable_int;
+ }
+
if (ITR_IS_DYNAMIC(vsi->rx_itr_setting)) {
rx = i40e_set_new_dynamic_itr(&q_vector->rx);
rxval = i40e_buildreg_itr(I40E_RX_ITR, q_vector->rx.itr);
@@ -1845,8 +1856,15 @@ static inline void i40e_update_enable_itr(struct i40e_vsi *vsi,
wr32(hw, INTREG(vector - 1), rxval);
}
+enable_int:
if (!test_bit(__I40E_DOWN, &vsi->state))
wr32(hw, INTREG(vector - 1), txval);
+
+ if (q_vector->itr_countdown)
+ q_vector->itr_countdown--;
+ else
+ q_vector->itr_countdown = ITR_COUNTDOWN_START;
+
}
/**
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.h b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
index 0fe7eb7..6779fb7 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.h
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.h
@@ -38,8 +38,8 @@
#define I40E_ITR_8K 0x003E
#define I40E_ITR_4K 0x007A
#define I40E_MAX_INTRL 0x3B /* reg uses 4 usec resolution */
-#define I40E_ITR_RX_DEF I40E_ITR_8K
-#define I40E_ITR_TX_DEF I40E_ITR_4K
+#define I40E_ITR_RX_DEF I40E_ITR_20K
+#define I40E_ITR_TX_DEF I40E_ITR_20K
#define I40E_ITR_DYNAMIC 0x8000 /* use top bit as a flag */
#define I40E_MIN_INT_RATE 250 /* ~= 1000000 / (I40E_MAX_ITR * 2) */
#define I40E_MAX_INT_RATE 500000 /* == 1000000 / (I40E_MIN_ITR * 2) */
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
index d76fe4a..47e9a90 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.c
@@ -348,10 +348,12 @@ static bool i40e_set_new_dynamic_itr(struct i40e_ring_container *rc)
* The math works out because the divisor is in 10^(-6) which
* turns the bytes/us input value into MB/s values, but
* make sure to use usecs, as the register values written
- * are in 2 usec increments in the ITR registers.
+ * are in 2 usec increments in the ITR registers, and make sure
+ * to use the smoothed values that the countdown timer gives us.
*/
- usecs = (rc->itr << 1);
+ usecs = (rc->itr << 1) * ITR_COUNTDOWN_START;
bytes_per_int = rc->total_bytes / usecs;
+
switch (new_latency_range) {
case I40E_LOWEST_LATENCY:
if (bytes_per_int > 10)
@@ -1245,8 +1247,18 @@ static inline void i40e_update_enable_itr(struct i40e_vsi *vsi,
int vector;
vector = (q_vector->v_idx + vsi->base_vector);
+
+ /* avoid dynamic calculation if in countdown mode OR if
+ * all dynamic is disabled
+ */
rxval = txval = i40e_buildreg_itr(I40E_ITR_NONE, 0);
+ if (q_vector->itr_countdown > 0 ||
+ (!ITR_IS_DYNAMIC(vsi->rx_itr_setting) &&
+ !ITR_IS_DYNAMIC(vsi->tx_itr_setting))) {
+ goto enable_int;
+ }
+
if (ITR_IS_DYNAMIC(vsi->rx_itr_setting)) {
rx = i40e_set_new_dynamic_itr(&q_vector->rx);
rxval = i40e_buildreg_itr(I40E_RX_ITR, q_vector->rx.itr);
@@ -1282,8 +1294,15 @@ static inline void i40e_update_enable_itr(struct i40e_vsi *vsi,
wr32(hw, INTREG(vector - 1), rxval);
}
+enable_int:
if (!test_bit(__I40E_DOWN, &vsi->state))
wr32(hw, INTREG(vector - 1), txval);
+
+ if (q_vector->itr_countdown)
+ q_vector->itr_countdown--;
+ else
+ q_vector->itr_countdown = ITR_COUNTDOWN_START;
+
}
/**
diff --git a/drivers/net/ethernet/intel/i40evf/i40e_txrx.h b/drivers/net/ethernet/intel/i40evf/i40e_txrx.h
index e2352b8..ebc1bf7 100644
--- a/drivers/net/ethernet/intel/i40evf/i40e_txrx.h
+++ b/drivers/net/ethernet/intel/i40evf/i40e_txrx.h
@@ -38,8 +38,8 @@
#define I40E_ITR_8K 0x003E
#define I40E_ITR_4K 0x007A
#define I40E_MAX_INTRL 0x3B /* reg uses 4 usec resolution */
-#define I40E_ITR_RX_DEF I40E_ITR_8K
-#define I40E_ITR_TX_DEF I40E_ITR_4K
+#define I40E_ITR_RX_DEF I40E_ITR_20K
+#define I40E_ITR_TX_DEF I40E_ITR_20K
#define I40E_ITR_DYNAMIC 0x8000 /* use top bit as a flag */
#define I40E_MIN_INT_RATE 250 /* ~= 1000000 / (I40E_MAX_ITR * 2) */
#define I40E_MAX_INT_RATE 500000 /* == 1000000 / (I40E_MIN_ITR * 2) */
diff --git a/drivers/net/ethernet/intel/i40evf/i40evf.h b/drivers/net/ethernet/intel/i40evf/i40evf.h
index 22841c6..22fc3d4 100644
--- a/drivers/net/ethernet/intel/i40evf/i40evf.h
+++ b/drivers/net/ethernet/intel/i40evf/i40evf.h
@@ -112,6 +112,8 @@ struct i40e_q_vector {
struct i40e_ring_container tx;
u32 ring_mask;
u8 num_ringpairs; /* total number of ring pairs in vector */
+#define ITR_COUNTDOWN_START 100
+ u8 itr_countdown; /* when 0 or 1 update ITR */
int v_idx; /* vector index in list */
char name[IFNAMSIZ + 9];
bool arm_wb_state;
diff --git a/drivers/net/ethernet/intel/i40evf/i40evf_main.c b/drivers/net/ethernet/intel/i40evf/i40evf_main.c
index ce99790..a44a42b 100644
--- a/drivers/net/ethernet/intel/i40evf/i40evf_main.c
+++ b/drivers/net/ethernet/intel/i40evf/i40evf_main.c
@@ -357,6 +357,7 @@ i40evf_map_vector_to_rxq(struct i40evf_adapter *adapter, int v_idx, int r_idx)
q_vector->rx.ring = rx_ring;
q_vector->rx.count++;
q_vector->rx.latency_range = I40E_LOW_LATENCY;
+ q_vector->itr_countdown = ITR_COUNTDOWN_START;
}
/**
@@ -377,6 +378,7 @@ i40evf_map_vector_to_txq(struct i40evf_adapter *adapter, int v_idx, int t_idx)
q_vector->tx.ring = tx_ring;
q_vector->tx.count++;
q_vector->tx.latency_range = I40E_LOW_LATENCY;
+ q_vector->itr_countdown = ITR_COUNTDOWN_START;
q_vector->num_ringpairs++;
q_vector->ring_mask |= BIT(t_idx);
}
--
2.4.3
--
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