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From: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
To: davem@davemloft.net
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>,
	netdev@vger.kernel.org, nhorman@redhat.com, sassmann@redhat.com,
	Gregg Leventhal <gleventhal@janestreet.com>,
	Andrew Bowers <andrewx.bowers@intel.com>,
	Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Subject: [net-next 11/14] ixgbe: Prevent u8 wrapping of ITR value to something less than 10us
Date: Tue, 10 Sep 2019 09:34:31 -0700	[thread overview]
Message-ID: <20190910163434.2449-12-jeffrey.t.kirsher@intel.com> (raw)
In-Reply-To: <20190910163434.2449-1-jeffrey.t.kirsher@intel.com>

From: Alexander Duyck <alexander.h.duyck@linux.intel.com>

There were a couple cases where the ITR value generated via the adaptive
ITR scheme could exceed 126. This resulted in the value becoming either 0
or something less than 10. Switching back and forth between a value less
than 10 and a value greater than 10 can cause issues as certain hardware
features such as RSC to not function well when the ITR value has dropped
that low.

Reported-by: Gregg Leventhal <gleventhal@janestreet.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index dc034f4e8cf6..a5398b691aa8 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -2623,7 +2623,7 @@ static void ixgbe_update_itr(struct ixgbe_q_vector *q_vector,
 		/* 16K ints/sec to 9.2K ints/sec */
 		avg_wire_size *= 15;
 		avg_wire_size += 11452;
-	} else if (avg_wire_size <= 1980) {
+	} else if (avg_wire_size < 1968) {
 		/* 9.2K ints/sec to 8K ints/sec */
 		avg_wire_size *= 5;
 		avg_wire_size += 22420;
@@ -2656,6 +2656,8 @@ static void ixgbe_update_itr(struct ixgbe_q_vector *q_vector,
 	case IXGBE_LINK_SPEED_2_5GB_FULL:
 	case IXGBE_LINK_SPEED_1GB_FULL:
 	case IXGBE_LINK_SPEED_10_FULL:
+		if (avg_wire_size > 8064)
+			avg_wire_size = 8064;
 		itr += DIV_ROUND_UP(avg_wire_size,
 				    IXGBE_ITR_ADAPTIVE_MIN_INC * 64) *
 		       IXGBE_ITR_ADAPTIVE_MIN_INC;
-- 
2.21.0


  parent reply	other threads:[~2019-09-10 16:34 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-10 16:34 [net-next 00/14][pull request] Intel Wired LAN Driver Updates 2019-09-10 Jeff Kirsher
2019-09-10 16:34 ` [net-next 01/14] ixgbe: fix memory leaks Jeff Kirsher
2019-09-10 16:34 ` [net-next 02/14] i40e: check __I40E_VF_DISABLE bit in i40e_sync_filters_subtask Jeff Kirsher
2019-09-10 16:34 ` [net-next 03/14] ixgbe: use skb_get_queue_mapping in tx path Jeff Kirsher
2019-09-10 16:34 ` [net-next 04/14] i40e: use ktime_get_real_ts64 instead of ktime_to_timespec64 Jeff Kirsher
2019-09-10 16:34 ` [net-next 05/14] i40e: remove I40E_AQC_ADD_CLOUD_FILTER_OIP Jeff Kirsher
2019-09-10 16:34 ` [net-next 06/14] i40e: mark additional missing bits as reserved Jeff Kirsher
2019-09-10 16:34 ` [net-next 07/14] i40e: fix missed "Negotiated" string in i40e_print_link_message() Jeff Kirsher
2019-09-10 16:34 ` [net-next 08/14] i40e: Fix message for other card without FEC Jeff Kirsher
2019-09-10 16:34 ` [net-next 09/14] i40e: use BIT macro to specify the cloud filter field flags Jeff Kirsher
2019-09-10 16:34 ` [net-next 10/14] i40e: clear __I40E_VIRTCHNL_OP_PENDING on invalid min Tx rate Jeff Kirsher
2019-09-10 16:34 ` Jeff Kirsher [this message]
2019-09-10 22:19   ` [net-next 11/14] ixgbe: Prevent u8 wrapping of ITR value to something less than 10us Alexander Duyck
2019-09-11  8:24   ` David Miller
2019-09-10 16:34 ` [net-next 12/14] iavf: fix MAC address setting for VFs when filter is rejected Jeff Kirsher
2019-09-10 16:34 ` [net-next 13/14] net/ixgbevf: make array api static const, makes object smaller Jeff Kirsher
2019-09-10 16:34 ` [net-next 14/14] i40e: fix potential RX buffer starvation for AF_XDP Jeff Kirsher

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