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authorJacob Keller <jacob.e.keller@intel.com>2016-06-10 00:56:05 +0300
committerJeff Kirsher <jeffrey.t.kirsher@intel.com>2016-08-29 11:31:03 +0300
commit5b9e4432db038eefcafe2be468e3adaf2edbbe91 (patch)
treebf647b3bb1a6f87f5dcf918519ffe349ef9f5549 /drivers/net/ethernet/intel/fm10k
parente59a393d089d08a4622de07f941dd3629fcaec6a (diff)
downloadlinux-5b9e4432db038eefcafe2be468e3adaf2edbbe91.tar.xz
fm10k: use software values when checking for Tx hangs in hot path
A previous patch added support to check for hardware Tx pending in the fm10k_down routine. This support was intended to ensure that we accurately check what the hardware state is. However, checking for Tx hangs in this manor during the hotpath results in a large performance hit. Avoid this by making the hotpath check use the SW counters instead. Fixes: a0f53cf49cb0 ("fm10k: use actual hardware registers when checking for pending Tx", 2016-06-08) Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Diffstat (limited to 'drivers/net/ethernet/intel/fm10k')
-rw-r--r--drivers/net/ethernet/intel/fm10k/fm10k.h2
-rw-r--r--drivers/net/ethernet/intel/fm10k/fm10k_main.c19
-rw-r--r--drivers/net/ethernet/intel/fm10k/fm10k_pci.c2
3 files changed, 17 insertions, 6 deletions
diff --git a/drivers/net/ethernet/intel/fm10k/fm10k.h b/drivers/net/ethernet/intel/fm10k/fm10k.h
index c4cf08dcf5af..75429f2bbc97 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k.h
+++ b/drivers/net/ethernet/intel/fm10k/fm10k.h
@@ -458,7 +458,7 @@ __be16 fm10k_tx_encap_offload(struct sk_buff *skb);
netdev_tx_t fm10k_xmit_frame_ring(struct sk_buff *skb,
struct fm10k_ring *tx_ring);
void fm10k_tx_timeout_reset(struct fm10k_intfc *interface);
-u64 fm10k_get_tx_pending(struct fm10k_ring *ring);
+u64 fm10k_get_tx_pending(struct fm10k_ring *ring, bool in_sw);
bool fm10k_check_tx_hang(struct fm10k_ring *tx_ring);
void fm10k_alloc_rx_buffers(struct fm10k_ring *rx_ring, u16 cleaned_count);
diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_main.c b/drivers/net/ethernet/intel/fm10k/fm10k_main.c
index e9767b6366a8..0d6e69d1586a 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k_main.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_main.c
@@ -1128,13 +1128,24 @@ static u64 fm10k_get_tx_completed(struct fm10k_ring *ring)
return ring->stats.packets;
}
-u64 fm10k_get_tx_pending(struct fm10k_ring *ring)
+/**
+ * fm10k_get_tx_pending - how many Tx descriptors not processed
+ * @ring: the ring structure
+ * @in_sw: is tx_pending being checked in SW or in HW?
+ */
+u64 fm10k_get_tx_pending(struct fm10k_ring *ring, bool in_sw)
{
struct fm10k_intfc *interface = ring->q_vector->interface;
struct fm10k_hw *hw = &interface->hw;
+ u32 head, tail;
- u32 head = fm10k_read_reg(hw, FM10K_TDH(ring->reg_idx));
- u32 tail = fm10k_read_reg(hw, FM10K_TDT(ring->reg_idx));
+ if (likely(in_sw)) {
+ head = ring->next_to_clean;
+ tail = ring->next_to_use;
+ } else {
+ head = fm10k_read_reg(hw, FM10K_TDH(ring->reg_idx));
+ tail = fm10k_read_reg(hw, FM10K_TDT(ring->reg_idx));
+ }
return ((head <= tail) ? tail : tail + ring->count) - head;
}
@@ -1143,7 +1154,7 @@ bool fm10k_check_tx_hang(struct fm10k_ring *tx_ring)
{
u32 tx_done = fm10k_get_tx_completed(tx_ring);
u32 tx_done_old = tx_ring->tx_stats.tx_done_old;
- u32 tx_pending = fm10k_get_tx_pending(tx_ring);
+ u32 tx_pending = fm10k_get_tx_pending(tx_ring, true);
clear_check_for_tx_hang(tx_ring);
diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_pci.c b/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
index 377a3fbb779f..20c2a0cf83da 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
@@ -1699,7 +1699,7 @@ void fm10k_down(struct fm10k_intfc *interface)
/* start checking at the last ring to have pending Tx */
for (; i < interface->num_tx_queues; i++)
- if (fm10k_get_tx_pending(interface->tx_ring[i]))
+ if (fm10k_get_tx_pending(interface->tx_ring[i], false))
break;
/* if all the queues are drained, we can break now */