diff options
| author | Jesse Brandeburg <jesse.brandeburg@intel.com> | 2015-09-28 20:16:54 +0200 |
|---|---|---|
| committer | Jeff Kirsher <jeffrey.t.kirsher@intel.com> | 2015-10-20 00:35:12 +0200 |
| commit | ee2319cf17ee64bbd0096f2f8f3f8390c93b1e39 (patch) | |
| tree | d8fb0d00f1226eb764ca532f0fbbb4a2f5835520 /drivers/net/ethernet/intel/i40e/i40e_txrx.c | |
| parent | i40e/i40evf: change dynamic interrupt thresholds (diff) | |
| download | linux-ee2319cf17ee64bbd0096f2f8f3f8390c93b1e39.tar.xz linux-ee2319cf17ee64bbd0096f2f8f3f8390c93b1e39.zip | |
i40e/i40evf: adjust interrupt throttle less frequently
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@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Diffstat (limited to 'drivers/net/ethernet/intel/i40e/i40e_txrx.c')
| -rw-r--r-- | drivers/net/ethernet/intel/i40e/i40e_txrx.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c index 7aea14389d7b..006f0fb4720c 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; + } /** |