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Date: Tue, 15 Sep 2015 17:36:31 -0700
From: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
To: davem@...emloft.net
Cc: Jacob Keller <jacob.e.keller@...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 06/18] fm10k: update fm10k_slot_warn to use pcie_get_minimum link
From: Jacob Keller <jacob.e.keller@...el.com>
This is useful in cases where we connect to a slot at Gen3, but the slot
is behind a bus which only connected at Gen2. This generally only
happens when a PCIe switch is in the sequence of devices, and can be
very confusing when you see slow performance with no obvious cause.
I am aware this patch has a few lines that break 80 characters, but
there does not seem to be a readable way to format them to less than 80
characters. Suggestions welcome.
Signed-off-by: Jacob Keller <jacob.e.keller@...el.com>
Tested-by: Krishneil Singh <krishneil.k.singh@...el.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
---
drivers/net/ethernet/intel/fm10k/fm10k_pci.c | 105 +++++++++++++++++++--------
1 file changed, 76 insertions(+), 29 deletions(-)
diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_pci.c b/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
index 8413ab5..2d87c32 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
+++ b/drivers/net/ethernet/intel/fm10k/fm10k_pci.c
@@ -1705,22 +1705,86 @@ static int fm10k_sw_init(struct fm10k_intfc *interface,
static void fm10k_slot_warn(struct fm10k_intfc *interface)
{
- struct device *dev = &interface->pdev->dev;
+ enum pcie_link_width width = PCIE_LNK_WIDTH_UNKNOWN;
+ enum pci_bus_speed speed = PCI_SPEED_UNKNOWN;
struct fm10k_hw *hw = &interface->hw;
+ int max_gts = 0, expected_gts = 0;
- if (hw->mac.ops.is_slot_appropriate(hw))
+ if (pcie_get_minimum_link(interface->pdev, &speed, &width) ||
+ speed == PCI_SPEED_UNKNOWN || width == PCIE_LNK_WIDTH_UNKNOWN) {
+ dev_warn(&interface->pdev->dev,
+ "Unable to determine PCI Express bandwidth.\n");
return;
+ }
+
+ switch (speed) {
+ case PCIE_SPEED_2_5GT:
+ /* 8b/10b encoding reduces max throughput by 20% */
+ max_gts = 2 * width;
+ break;
+ case PCIE_SPEED_5_0GT:
+ /* 8b/10b encoding reduces max throughput by 20% */
+ max_gts = 4 * width;
+ break;
+ case PCIE_SPEED_8_0GT:
+ /* 128b/130b encoding has less than 2% impact on throughput */
+ max_gts = 8 * width;
+ break;
+ default:
+ dev_warn(&interface->pdev->dev,
+ "Unable to determine PCI Express bandwidth.\n");
+ return;
+ }
+
+ dev_info(&interface->pdev->dev,
+ "PCI Express bandwidth of %dGT/s available\n",
+ max_gts);
+ dev_info(&interface->pdev->dev,
+ "(Speed:%s, Width: x%d, Encoding Loss:%s, Payload:%s)\n",
+ (speed == PCIE_SPEED_8_0GT ? "8.0GT/s" :
+ speed == PCIE_SPEED_5_0GT ? "5.0GT/s" :
+ speed == PCIE_SPEED_2_5GT ? "2.5GT/s" :
+ "Unknown"),
+ hw->bus.width,
+ (speed == PCIE_SPEED_2_5GT ? "20%" :
+ speed == PCIE_SPEED_5_0GT ? "20%" :
+ speed == PCIE_SPEED_8_0GT ? "<2%" :
+ "Unknown"),
+ (hw->bus.payload == fm10k_bus_payload_128 ? "128B" :
+ hw->bus.payload == fm10k_bus_payload_256 ? "256B" :
+ hw->bus.payload == fm10k_bus_payload_512 ? "512B" :
+ "Unknown"));
- dev_warn(dev,
- "For optimal performance, a %s %s slot is recommended.\n",
- (hw->bus_caps.width == fm10k_bus_width_pcie_x1 ? "x1" :
- hw->bus_caps.width == fm10k_bus_width_pcie_x4 ? "x4" :
- "x8"),
- (hw->bus_caps.speed == fm10k_bus_speed_2500 ? "2.5GT/s" :
- hw->bus_caps.speed == fm10k_bus_speed_5000 ? "5.0GT/s" :
- "8.0GT/s"));
- dev_warn(dev,
- "A slot with more lanes and/or higher speed is suggested.\n");
+ switch (hw->bus_caps.speed) {
+ case fm10k_bus_speed_2500:
+ /* 8b/10b encoding reduces max throughput by 20% */
+ expected_gts = 2 * hw->bus_caps.width;
+ break;
+ case fm10k_bus_speed_5000:
+ /* 8b/10b encoding reduces max throughput by 20% */
+ expected_gts = 4 * hw->bus_caps.width;
+ break;
+ case fm10k_bus_speed_8000:
+ /* 128b/130b encoding has less than 2% impact on throughput */
+ expected_gts = 8 * hw->bus_caps.width;
+ break;
+ default:
+ dev_warn(&interface->pdev->dev,
+ "Unable to determine expected PCI Express bandwidth.\n");
+ return;
+ }
+
+ if (max_gts < expected_gts) {
+ dev_warn(&interface->pdev->dev,
+ "This device requires %dGT/s of bandwidth for optimal performance.\n",
+ expected_gts);
+ dev_warn(&interface->pdev->dev,
+ "A %sslot with x%d lanes is suggested.\n",
+ (hw->bus_caps.speed == fm10k_bus_speed_2500 ? "2.5GT/s " :
+ hw->bus_caps.speed == fm10k_bus_speed_5000 ? "5.0GT/s " :
+ hw->bus_caps.speed == fm10k_bus_speed_8000 ? "8.0GT/s " : ""),
+ hw->bus_caps.width);
+ }
}
/**
@@ -1739,7 +1803,6 @@ static int fm10k_probe(struct pci_dev *pdev,
{
struct net_device *netdev;
struct fm10k_intfc *interface;
- struct fm10k_hw *hw;
int err;
err = pci_enable_device_mem(pdev);
@@ -1783,7 +1846,6 @@ static int fm10k_probe(struct pci_dev *pdev,
interface->netdev = netdev;
interface->pdev = pdev;
- hw = &interface->hw;
interface->uc_addr = ioremap(pci_resource_start(pdev, 0),
FM10K_UC_ADDR_SIZE);
@@ -1825,21 +1887,6 @@ static int fm10k_probe(struct pci_dev *pdev,
/* Register PTP interface */
fm10k_ptp_register(interface);
- /* print bus type/speed/width info */
- dev_info(&pdev->dev, "(PCI Express:%s Width: %s Payload: %s)\n",
- (hw->bus.speed == fm10k_bus_speed_8000 ? "8.0GT/s" :
- hw->bus.speed == fm10k_bus_speed_5000 ? "5.0GT/s" :
- hw->bus.speed == fm10k_bus_speed_2500 ? "2.5GT/s" :
- "Unknown"),
- (hw->bus.width == fm10k_bus_width_pcie_x8 ? "x8" :
- hw->bus.width == fm10k_bus_width_pcie_x4 ? "x4" :
- hw->bus.width == fm10k_bus_width_pcie_x1 ? "x1" :
- "Unknown"),
- (hw->bus.payload == fm10k_bus_payload_128 ? "128B" :
- hw->bus.payload == fm10k_bus_payload_256 ? "256B" :
- hw->bus.payload == fm10k_bus_payload_512 ? "512B" :
- "Unknown"));
-
/* print warning for non-optimal configurations */
fm10k_slot_warn(interface);
--
2.4.3
--
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