summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorJesse Brandeburg <jesse.brandeburg@intel.com>2021-09-20 12:30:14 -0700
committerTony Nguyen <anthony.l.nguyen@intel.com>2021-10-19 10:45:17 -0700
commit23be7075b31863da9cf3983aebcc8ff7537c06ac (patch)
tree239ccf6c47bf7c1df73ab43561e123f3ac249c20
parentd16a4f45f3a3afcb56910a7242cc621c071e80e4 (diff)
downloadlinux-23be7075b31863da9cf3983aebcc8ff7537c06ac.tar.gz
linux-23be7075b31863da9cf3983aebcc8ff7537c06ac.tar.bz2
linux-23be7075b31863da9cf3983aebcc8ff7537c06ac.zip
ice: fix software generating extra interrupts
The driver tried to work around missing completion events that occurred while interrupts are disabled, by triggering a software interrupt whenever we exit polling (but we had to have polled at least once). This was causing a *lot* of extra interrupts for some workloads like NVMe over TCP, which resulted in regressions in performance. It was also visible when polling didn't prevent interrupts when busy_poll was enabled. Fix the extra interrupts by utilizing our previously unused 3rd ITR (interrupt throttle) index and set it to 20K interrupts per second, and then trigger a software interrupt within that rate limit. While here, slightly refactor the code to avoid an overwrite of a local variable in the case of wb_en = true. Fixes: b7306b42beaf ("ice: manage interrupts during poll exit") Signed-off-by: Jesse Brandeburg <jesse.brandeburg@intel.com> Tested-by: Gurucharan G <gurucharanx.g@intel.com> Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
-rw-r--r--drivers/net/ethernet/intel/ice/ice_hw_autogen.h1
-rw-r--r--drivers/net/ethernet/intel/ice/ice_txrx.c26
2 files changed, 16 insertions, 11 deletions
diff --git a/drivers/net/ethernet/intel/ice/ice_hw_autogen.h b/drivers/net/ethernet/intel/ice/ice_hw_autogen.h
index 76021d977b60..a49082485642 100644
--- a/drivers/net/ethernet/intel/ice/ice_hw_autogen.h
+++ b/drivers/net/ethernet/intel/ice/ice_hw_autogen.h
@@ -182,6 +182,7 @@
#define GLINT_DYN_CTL_INTERVAL_S 5
#define GLINT_DYN_CTL_INTERVAL_M ICE_M(0xFFF, 5)
#define GLINT_DYN_CTL_SW_ITR_INDX_ENA_M BIT(24)
+#define GLINT_DYN_CTL_SW_ITR_INDX_S 25
#define GLINT_DYN_CTL_SW_ITR_INDX_M ICE_M(0x3, 25)
#define GLINT_DYN_CTL_WB_ON_ITR_M BIT(30)
#define GLINT_DYN_CTL_INTENA_MSK_M BIT(31)
diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c
index 1373b97b117a..8f908af9bdd5 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx.c
+++ b/drivers/net/ethernet/intel/ice/ice_txrx.c
@@ -1361,21 +1361,25 @@ static void ice_enable_interrupt(struct ice_q_vector *q_vector)
if (test_bit(ICE_DOWN, vsi->state))
return;
- /* When exiting WB_ON_ITR, let ITR resume its normal
- * interrupts-enabled path.
+ /* trigger an ITR delayed software interrupt when exiting busy poll, to
+ * make sure to catch any pending cleanups that might have been missed
+ * due to interrupt state transition. If busy poll or poll isn't
+ * enabled, then don't update ITR, and just enable the interrupt.
*/
- if (wb_en)
+ if (!wb_en) {
+ itr_val = ice_buildreg_itr(ICE_ITR_NONE, 0);
+ } else {
q_vector->wb_on_itr = false;
- itr_val = ice_buildreg_itr(ICE_ITR_NONE, 0);
- /* trigger an immediate software interrupt when exiting
- * busy poll, to make sure to catch any pending cleanups
- * that might have been missed due to interrupt state
- * transition.
- */
- if (wb_en) {
+ /* do two things here with a single write. Set up the third ITR
+ * index to be used for software interrupt moderation, and then
+ * trigger a software interrupt with a rate limit of 20K on
+ * software interrupts, this will help avoid high interrupt
+ * loads due to frequently polling and exiting polling.
+ */
+ itr_val = ice_buildreg_itr(ICE_IDX_ITR2, ICE_ITR_20K);
itr_val |= GLINT_DYN_CTL_SWINT_TRIG_M |
- GLINT_DYN_CTL_SW_ITR_INDX_M |
+ ICE_IDX_ITR2 << GLINT_DYN_CTL_SW_ITR_INDX_S |
GLINT_DYN_CTL_SW_ITR_INDX_ENA_M;
}
wr32(&vsi->back->hw, GLINT_DYN_CTL(q_vector->reg_idx), itr_val);