Thread (5 messages) flat view 5 messages, 4 authors, 2014-05-20

Re: [PATCH 1/8] ixgbe: Out of line ixgbe_read/write_reg

From: Rustad, Mark D <hidden>
Date: 2014-05-19 22:01:06
Also in: lkml

On May 16, 2014, at 2:43 PM, Andi Kleen [off-list ref] wrote:
From: Andi Kleen <redacted>

ixgbe_read_reg and ixgbe_write_reg are frequently called and are very big
because they have complex error handling code.
Actually, this patch doesn't do anything to ixgbe_write_reg, which would almost certainly be very bad for performance, but instead changes ixgbe_write_reg64. The latter is not in a performance-sensitive path, but is only called from one site, so there is little reason to take it out-of-line.

I already have a patch in queue to make ixgbe_read_reg out-of-line, because it does have a very costly memory footprint inline, as you have found.
quoted hunk ↗ jump to hunk
Moving them out of line saves ~27k text in the ixgbe driver.

  text	   data	    bss	    dec	    hex	filename
14220873	2008072	1507328	17736273	10ea251	vmlinux-before-ixgbe
14193673	2003976	1507328	17704977	10e2811	vmlinux-ixgbe

Cc: netdev@vger.kernel.org
Cc: Jeff Kirsher <redacted>
Signed-off-by: Andi Kleen <redacted>
---
drivers/net/ethernet/intel/ixgbe/ixgbe_common.h | 22 ++--------------------
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c   | 22 ++++++++++++++++++++++
2 files changed, 24 insertions(+), 20 deletions(-)
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
index f12c40f..05f094d 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_common.h
@@ -162,28 +162,10 @@ static inline void writeq(u64 val, void __iomem *addr)
}
#endif

-static inline void ixgbe_write_reg64(struct ixgbe_hw *hw, u32 reg, u64 value)
-{
-	u8 __iomem *reg_addr = ACCESS_ONCE(hw->hw_addr);
+void ixgbe_write_reg64(struct ixgbe_hw *hw, u32 reg, u64 value);
+u32 ixgbe_read_reg(struct ixgbe_hw *hw, u32 reg);

-	if (ixgbe_removed(reg_addr))
-		return;
-	writeq(value, reg_addr + reg);
-}
#define IXGBE_WRITE_REG64(a, reg, value) ixgbe_write_reg64((a), (reg), (value))
-
-static inline u32 ixgbe_read_reg(struct ixgbe_hw *hw, u32 reg)
-{
-	u8 __iomem *reg_addr = ACCESS_ONCE(hw->hw_addr);
-	u32 value;
-
-	if (ixgbe_removed(reg_addr))
-		return IXGBE_FAILED_READ_REG;
-	value = readl(reg_addr + reg);
-	if (unlikely(value == IXGBE_FAILED_READ_REG))
-		ixgbe_check_remove(hw, reg);
-	return value;
-}
#define IXGBE_READ_REG(a, reg) ixgbe_read_reg((a), (reg))

#define IXGBE_WRITE_REG_ARRAY(a, reg, offset, value) \
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index d62e7a2..5f81f62 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -371,6 +371,28 @@ void ixgbe_write_pci_cfg_word(struct ixgbe_hw *hw, u32 reg, u16 value)
	pci_write_config_word(adapter->pdev, reg, value);
}

+void ixgbe_write_reg64(struct ixgbe_hw *hw, u32 reg, u64 value)
+{
+	u8 __iomem *reg_addr = ACCESS_ONCE(hw->hw_addr);
+
+	if (ixgbe_removed(reg_addr))
+		return;
+	writeq(value, reg_addr + reg);
+}
+
+u32 ixgbe_read_reg(struct ixgbe_hw *hw, u32 reg)
+{
+	u8 __iomem *reg_addr = ACCESS_ONCE(hw->hw_addr);
+	u32 value;
+
+	if (ixgbe_removed(reg_addr))
+		return IXGBE_FAILED_READ_REG;
+	value = readl(reg_addr + reg);
+	if (unlikely(value == IXGBE_FAILED_READ_REG))
+		ixgbe_check_remove(hw, reg);
+	return value;
+}
+
static void ixgbe_service_event_complete(struct ixgbe_adapter *adapter)
{
	BUG_ON(!test_bit(__IXGBE_SERVICE_SCHED, &adapter->state));
-- 
1.9.0

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-- 
Mark Rustad, Networking Division, Intel Corporation
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